Where to (legally) acquire content to play on RetroPie

Auster

Cosmic Courier: Trapped in Limbo: https://bryanrollins.itch.io/cosmic-courier-trapped-in-limbo
Platform: GameBoy
The ROM is the downloadable .gb file.

Witch n' Wiz: https://mhughson.itch.io/witch-n-wiz
Platform: NES
The ROM is the downloadable .nes file.

FROM BELOW: https://mhughson.itch.io/from-below
Platform: NES & Nintendo VS. System (arcade)
The NES ROM is the file downloadable from the option "NES ROM [version number]". The Nintendo VS. Arcade System ROM are the files from the option "Vs. System ROMs [version number]", and may need compiling to run in MAME and the like.

Street Fighter II NE (fan game & demo): https://parisoft.itch.io/street-fighter-ii-ne-demo
Platform: NES
The ROM is the downloadable .nes file.

Berzerk: https://parisoft.itch.io/berzerk
Platform: NES
Has 2 ROMs, both in the .nes format. Also mind there are some reports of certain emulators having different compatibilities with the ROMs, so if one ROM doesn't work, try the other.

DUCKSTROMA: https://narwhal.itch.io/duckstroma
Platforms: ZX Spectrum (either 48K or 128K), MSX & NES
Each downloadable file is a ROM for a specific system (properly identified). Also, the NES version is an old prototype.

PTM: https://narwhal.itch.io/ptm
Platform: ZX Spectrum (either 48K or 128K)
The ROM is the .TAP file inside the downloadable .zip file.

OCTUKITTY: https://narwhal.itch.io/octukitty
Platform: ZX Spectrum (either 48K or 128K)
The ROM is the .tap file inside the downloadable .zip file.

BLIMPGEDDON: https://narwhal.itch.io/blimpgeddon
Platform: ZX Spectrum (either 48K or 128K)
The ROM is the .tap file inside the downloadable .zip file.

Cocoa 2: Twenty Four Hour Parsley People: https://minilop.itch.io/24hour
Platform: ZX Spectrum 128K
Has 3 versions of the demo (the free files), one in English, one in Portuguese and one in Spanish, and it has 3 versions of the full release (the paid files), each with one of the languages mentioned before. The ROMs are the .tap files inside the downloadable files.

Cocoa and the Time Machine: https://minilop.itch.io/cocoa-and-the-time-machine
Platforms: ZX Spectrum (either 48K or 128K) & MSX
Has 3 files for ZX Spectrum 48K, each with a language (Portuguese, English & Spanish), 3 files for the ZX Spectrum 128K (also each with a language from the ones mentioned before) and 1 file for the MSX (only in English)

themazingness

@auster Wow, you are the master at finding these itch.io ROMS. Thanks for all the work you are doing!

Auster

@themazingness Glad to be of help!

Btw, a tip: if you see a homebrew game on Itchio, check the dev's other works. Chances are the game you saw isn't the only one that can be emulated. Following these devs helps too, so that you get notified of homebrew/emulation-related stuff from them (just mind your feed can get kinda spammy if you follow too many devs; I know by experience "<.< ).

And sorry for not making a single post with all the games I find, but I'd find a single post with 200+ games a bit overwhelming if I was a passer-by. (plus, it would take a long time to check so many games, specially since some things about some games are not quite clear, like Cocoa 1 only having multiple languages in the ZX Spectrum version)

And here's some more games:

La Reliquia: https://roolandoo.itch.io/lareliquia
Platforms: ZX Spectrum & MSX
The ROMs are the .tap (ZX) and .dsk/.rom (MSX) files inside the downloadable .zip files. Both have 2 versions, one in Spanish and one in English. And both ZX ROMs have 2 variants, one for 48K models, and one for 128K models.

S.o.L.o.: https://roolandoo.itch.io/solo
Platform: ZX Spectrum 128K
Has 2 versions, one in English, and one in Spanish. The ROMs are the .tap files inside the downloadable .zip files.

Black & White: https://greenwebsevilla.itch.io/black-and-white
Platform: ZX Spectrum 128K
Has a demo and a full release in the same page. The demo is the downloadable .tap file in the demo part of the page. I don't own the full game yet, but it's likely the same as the demo.

Ninjakul 2: The Last Ninja: https://greenwebsevilla.itch.io/ninjakul-2-the-last-ninja
Platform: ZX Spectrum 128k
I don't own the game yet, but according to to the description, it does come with a ROM.

Ninjakul in the AUIC Temple: https://greenwebsevilla.itch.io/ninjakul-in-the-auic-temple
Platform: ZX Spectrum 128k
The ROM is the downloadable .tap file.

Vampire Slayer (demo): https://greenwebsevilla.itch.io/vampire-slayer
Platform: ZX Spectrum 128k
Has two versions, one in English and one in Spanish. The ROMs are the downloadable .tap files. Also the dev (s) plan to make a full version of it in the future.

Bat Boy: https://greenwebsevilla.itch.io/bat-boy
Platform: ZX Spectrum (48/128K)
I don't own the game yet, but according to to the description, it does come with a ROM.

Vampire Vengeance: https://endaraues.itch.io/vampire
Platform: ZX Spectrum
The ROM is the downloadable .tap file.

Pumpkin Poe: https://endaraues.itch.io/pumpkin-poe
Platform: ZX Spectrum
The ROM is the downloadable .tap file.

Droid Buster: https://endaraues.itch.io/droid-buster
Platform: ZX Spectrum
The ROM is the downloadable .tap file.

AtomiCat: https://endaraues.itch.io/atomicat
Platform: ZX Spectrum
The ROM is the downloadable .tap file.

Soul of the Beast: https://aeriform.itch.io/beast
Platform: Atari 2600
The ROM is the downloadable .bin file.

Auster

First, a question: AtariAge is legit, right? I see them being mentioned a few times here, and I found even some BIOS files while looking at their site.

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Nebs 'n Debs: https://dullahan-software.itch.io/nebs-n-debs
Platform: NES
I don't own the game so I can't check, but by the description, it likely comes with a ROM.

CRNVRS (Portuguese version): https://dakicorp.itch.io/crnvrs-microconto
Platform: GameBoy
The ROM is the .gb file inside the downloadable .zip file.

Upsad Down: https://fadest.itch.io/upsad-down
Platform: NES
The ROM is the downloadable .nes file.

Asteroids Chasers: https://fadest.itch.io/achaser-gb
Platform: GameBoy
The ROM is the downloadable .gb file.

A Bug's Trip Redux Demo: https://fadest.itch.io/a-bugs-trip-redux-demo
Platform: Atari Lynx
The ROM is the downloadable .lnx file.

A Bug's Lynx: https://fadest.itch.io/a-bugs-lynx
Platform: Atari Lynx
The ROM is the .lnx file inside the downloadable .zip file.

Asteroids Chasers: https://fadest.itch.io/achasers
Platform: Atari Lynx
The ROMs are the downloadable .lnx files. Likely "AChasers20200816.lnx" is the most recent update.

Raid on TriCity: https://fadest.itch.io/raid-on-tricity
Platform: Atari Lynx
The ROM is the .lnx file inside the downloadable .zip file.

Leaf and the forgotten temple (Ynxa version): https://fadest.itch.io/ynxa
Platform: Atari Lynx
The ROM is the .lnx file inside the downloadable .zip file.

Yastuna - The Alchemy of Cubes: https://fadest.itch.io/yastuna-the-alchemy-of-cubes
Platform: Atari Lynx
The ROM is the .lnx file inside the downloadable .zip file.

Yastuna 2 - the Space Incident: https://fadest.itch.io/yastuna-2-the-space-incident
Platform: Atari Lynx
The ROM is the .lnx file inside the downloadable .zip file.

Saving Santa Tree - LynxMas 2020: https://fadest.itch.io/lynxmas-2020
Platform: Atari Lynx
The ROM is the .lnx file inside the downloadable .zip file.

Cyberpunk Experiment 2037: https://fadest.itch.io/cyberpunk-2037
Platform: Atari Lynx
The ROMs are the downloadable .lnx files. They appear to be identified by update date, such as "c37-20200421.lnx" being from the update from April 21, 2020.

Doodle World (both demo & full release): https://natepeters.itch.io/doodle-world
Platform: NES
The demo is the .nes file inside the downloadable .zip file in the store page. And I don't own the full release yet, but according to the description, it comes with a ROM too.

+18 game below, contains explicity sexual intercourse; don't open if you're a minor.
Mating Season GB: https://peddverse.itch.io/mating-season-gb
Platform: GameBoy
Has multiple .gb ROMs inside. The most recent one is probably the one with the most recent updates as well. Also by the description and the last time Itchio says the game had an update, it appears to be mostly complete, but ultimately abandoned.

Clyde

@auster said in Where to (legally) acquire content to play on RetroPie:

+18 game below, contains explicity sexual intercourse; don't open if you're a minor.

You know that this remark will make every minor click on that link, don't you? 😉

themazingness

@Auster Regarding Atari Age, I can't confirm they aren't legit, but I'm skeptical they are. Watching their YouTube videos, I noticed Princess Rescue uses the Super Mario music and characters, and Nintendo doesn't go handing out permission. Scramble didn't indicate permission from Konami but it did show their copyright but no dev credits to whoever ported it. Adventure II XE says Atari gave permission. Mario is what made me doubt they really get permissions for everything if much of anything.

Regardless, the homebrews without IP from other companies would be legit unless somehow the content is being sold without the homebrew devs' permission.

Auster

@themazingness Thanks for the input.

Just in case, I contacted Atari's customer support.
I'll send their reply here if/when they answer the support ticket.

Auster

2 updates:

First...

@auster said in Where to (legally) acquire content to play on RetroPie:

La Citadelle du Chaos: https://vetea.itch.io/la-citadelle-du-chaos-megadrive
Platform: Sega Genesis/Mega Drive
The downloadable file is the ROM. No need to rename or change its extension. Only available in French.

It was updated to the final version a few hours ago. Now it seems to be only available in English, but just in case, I asked the dev if it can still be played in French.

The second update is about AtariAge.

The e-mail I sent:

Hello.

Is the site atariage(dot)com legal?
I see no mentions from or about Atari itself regarding it.
Also, they share copyrighted materials in their site, such as BIOS of certain Atari consoles, but I couldn't find any mentions saying they're allowed or not to do so.

Thanks in advance and thank you for your time.

The reply I received:

Thank you for your question. That site is not an Atari site but more of a forum. People talk about everything from games to problems. Some of them might work and some of them might damage your unit. We do not advise you follow their steps. If you need assistance, please send in a support ticket and a certified Atari Agent will be assigned to your ticket for authentic support.

Best Regards,

Atari Support

So, while they didn't they didn't specify whether or not AtariAge has the rights to share copyrighted files (just sent another ticket to clarify the rights part), the support advising against using AtariAge also makes me unsure whether or not the site can be trusted.

Hopefully I can get a clearer answer from the new ticket.

Auster

@auster said in Where to (legally) acquire content to play on RetroPie:

@auster said in Where to (legally) acquire content to play on RetroPie:

La Citadelle du Chaos: https://vetea.itch.io/la-citadelle-du-chaos-megadrive
Platform: Sega Genesis/Mega Drive
The downloadable file is the ROM. No need to rename or change its extension. Only available in French.

It was updated to the final version a few hours ago. Now it seems to be only available in English, but just in case, I asked the dev if it can still be played in French.

Little update - the dev explained how to change languages:

Auster

The Seance: https://quantumsheep.itch.io/the-seance
Platform: ZX Spectrum
I don't own the game yet, but according to the store page, includes 3 ROMs, one in the .tap format, one in the .z80 format and one in the .sna format. According to Retropie's systems information, all 3 should work in ZX Spectrum emulators.

A Very Sheepy Xmas: https://quantumsheep.itch.io/a-very-sheepy-xmas
Platform: ZX Spectrum
Same file formats as the one above.

Jumpin' Jupiter: https://quantumsheep.itch.io/jumpin-jupiter
Platform: ZX Spectrum
Same file formats as the others above.

Jumpin' Jupiter : Prelude: https://quantumsheep.itch.io/jumping-jupiter-prelude
Platform: ZX Spectrum
Same file formats as the others above.

Main Course - The Retro Cut: https://quantumsheep.itch.io/main-course-the-retro-cut
Platform: ZX Spectrum
Same file formats as the others above.

Last Train To Tranz-Central: https://quantumsheep.itch.io/last-train-to-tranz-central
Platform: ZX Spectrum
Same file formats as the others above. Part 1 of the game is included as a demo (also in the formats already mentioned).

Auster

Saw this on Twitter:

Can anyone confirm if a Wii ROM (and maybe even BIOS) can be obtained from the game? Might need compiling, tho.

EDIT 10/6/21: That Twitter account was either nuked or deleted. Maybe it's emulated indeed and a publisher/dev didn't like it?

Auster

@auster About AtariAge...

My second e-mail:

Thank you for your reply for the ticket #BZV-722-63716, but I have one last question:
As mentioned before, the site offers copyrighted files, such as system files/BIOS for Atari Lynx and Atari 5200, to download.
These files are available outside of the forum part of the site, in a stickied part of it, the "Systems" part in the top left, then in the "Emulation" part that appears in those same stickied options.
The question is, downloading these files would be considered piracy? Or do the site owners have the rights to share these files?

Their reply:

Thank you for the question. These links are there to help users with easy fixes. We do not mind if they use them. Remember though, we do NOT advise this. If you try and use the links I would use the ones from the actual Atari page.
Best Regards,
Atari Support

Sounds like Atari is fine with AtariAge sharing these files. Also, Atari has these files available as well? I couldn't find them in their site.

Auster

NESert Golfing: https://rainwarrior.itch.io/nesert-golfing
Platform: NES & Famicom Disk System
Has 3 ROMs. DGOLF.NES is the randomly generated NES version. DGOLF_TE.NES (Tournament Edition) is the version where you can set a generation seed so it isn't random. DGOLF.FDS is the Famicom Disk System ROM based on the DGOLF.NES version.

Lizard: https://rainwarrior.itch.io/lizard
Platforms: NES & MS-DOS (and also the more common PC OS's used today)
Includes both a demo and a full release of all the versions, all properly identified.

Rulent Tower (+16 y.o. rating, maybe?): https://setsune.itch.io/rulenttower
Platform: GameBoy
The ROM is the downloadable .gb file (written as ".ab" in the file preview, likely a typo). Mind that while there's nothing explicity, the game has multiple mentions to more riské stuff. And the development appears to have been halted for a while now.

Gift Catcher: https://drludos.itch.io/gift-catcher
Platform: Atari Lynx
The ROMs are properly specified in the downloadable files.
Also includes the source code if you want to make your own games for the platform.

The Last Super: https://drludos.itch.io/the-last-super
Platform: SNES
The ROM is properly specified in the downloadable files.
Also includes the source code if you want to make your own games for the platform.

Timeloop: https://drludos.itch.io/timeloop
Platform: Atari Lynx
The ROMs are properly specified in the downloadable files.
Also includes the source code if you want to make your own games for the platform.

Keeping SNES Alive!: https://drludos.itch.io/keeping-snes-alive
Platform: SNES
The ROM is properly specified in the downloadable files.
Also includes the source code if you want to make your own games for the platform.

Fishing for ATARI: https://drludos.itch.io/fishing-for-atari
Platform: Atari Lynx
The ROMs are included in the downloadable file.
Also includes the source code if you want to make your own games for the platform.

Yo-Yo Shuriken: https://drludos.itch.io/yo-yo-shuriken
Platform: SNES
The ROM is the downloadable .sfc file.

DMG Deals Damage: https://drludos.itch.io/dmg-deals-damage
Platform: GameBoy
The ROM is the downloadable .gb file.

Growing Ties: https://drludos.itch.io/growing-ties
Platform: Atari Lynx
The ROMs are inside the downloadable .zip file.

MeteoRain (GameShell Jam #1): https://drludos.itch.io/meteorain-gameshell-jam-1
Platform: Sega Genesis/Mega Drive
The ROM is the downloadable .bin file.

Sheep It Up!: https://drludos.itch.io/sheep-it-up-2600
Platform: Atari 2600
The ROMs are the downloadable files (differences specified).

30 Years of Nintendon't: https://drludos.itch.io/30-years-of-nintendont
Platform: Sega Genesis/Mega Drive
The ROM is the downloadable .bin file.

Sheep It Up!: https://drludos.itch.io/sheep-it-up
Platform: GameBoy
The ROM is the downloadable .gb file.

Break An Egg (0h Game Jam): https://drludos.itch.io/break-an-egg
Platform: Sega Genesis/Mega Drive
The ROM is the downloadable .bin file.
Also includes the source code if you want to make your own games for the platform.

Frog: https://boston-breams.itch.io/frog
Platform: NES
The ROM is the .nes file inside the downloadable .zip file.

Light From Within: https://atarath.itch.io/light-from-within
Platform: NES
The ROM is the downloadable .nes file.

Deep Blue: https://wendelscardua.itch.io/deep-blue
Platform: NES
The ROM is the downloadable .nes file.

NESDev '19 Compo Cart: https://action53.itch.io/compocart19
Platform: NES
Multiple games included inside the ROM. The ROM is the .nes file inside the downloadable .zip file.
These games, along with where to download them that I could find (as linked in the anthology page or the forums of the organizers), are...
down the rabbit hole we go

All games as separated ROMs but together in a single zip file: https://neshomebrew.ca/contest19/

Click in the "HERE" in the part that says "You can DOWNLOAD all the Category 1 entries HERE."
The ROMs are the .nes files inside.

Böbl (previously mentioned here), also available here: https://forums.nesdev.com/viewtopic.php?f=35&t=19718
Both ROMs are the .nes files in the first post.

Nalleland, also available here: https://nallebeorn.itch.io/nalleland
The ROM is the downloadable .nes file.
And also available here: https://forums.nesdev.com/viewtopic.php?f=35&t=19790
The ROM is the downloadable .nes file in the first post.

Blockage (previously mentioned here), also available here: https://forums.nesdev.com/viewtopic.php?f=35&t=19602
The ROM is the downloadable .nes file in the first post.

Veggie Invaders, also available here: https://forums.nesdev.com/viewtopic.php?t=19799
The ROM is the downloadable .nes file in the first post.

NIN NIN, also available here: https://forums.nesdev.com/viewtopic.php?f=35&t=19796
The ROM is the downloadable .nes file in the first post.

Bloodfall, also available here: https://forums.nesdev.com/viewtopic.php?f=35&t=19780
The ROM is the .nes file that can be downloaded from the part that says "ROM attached to this post (NROM)".

Falling Tiles, also available here: https://forums.nesdev.com/viewtopic.php?f=35&t=19696
The ROMs are the 2 downloadable .nes files spread across the post. Search for ".nes" (without quotation marks) with your browser's text search function (usually Ctrl F).

Hot Dance 2020: Dance!, also available here: https://forums.nesdev.com/viewtopic.php?f=35&t=19791
The ROM is the downloadable .nes file in the first post.

NNNNNN, also available here: https://www.bitethechili.com/nnnnnn/
The ROM is the .nes file inside the .zip file you can download from the "Download for NES" button.
And also available here: https://forums.nesdev.com/viewtopic.php?f=35&t=19579
Search for ".nes" with Ctrl F again.

Save the Kuin, also available here: https://kaffeeware.github.io/
The ROM is the .nes file in the part that says "download v05". Just click it to download.

Super City Mayor, also available here: https://globalgamejam.org/2020/games/super-city-mayor-3
The ROM is the .nes file inside the downloadable file "SuperMayor_Binary.zip"

Some sites linked in the anthology above that deserve special mentions:

Spanish site with a bunch of homebrews: https://www.mojontwins.com/juegos_mojonos/
Includes ROMs from Amstrad, Commodore 64, Master System, Mega Drive/Genesis, MS-DOS, MSX/MSX2, NES, SG-1000, ZX Spectrum and ZX81.
Some appear to be available in multiple languages.

Another site with multiple homebrews: https://www.bitethechili.com/
Includes ROMs for NES, Atari 2600, Dreamcast, GameBoy Advance and Nintendo DS.

Rodas Cross (demo): https://github.com/kaffeeware/snes_roms
Platform: SNES
Has 3 versions of the demo. They're the .smc files listed in the site.

Auster

The Cowlitz Gamers' Lost Adventure: https://mteegfx.itch.io/lost
Platforms: NES & ZX Spectrum
The ROMs are the .nes (NES) and .tap (ZX Spectrum) files inside the downloadable .zip file.

The Cowlitz Gamers' 2nd Adventure: https://mteegfx.itch.io/cowlitz
Platform: NES
Has 2 ROMs, both with the .nes format. Not sure what's the difference between them. They're included in the "Release Pack" zip file.

Gruniożerca 2: The Great Cavy Rescue!: https://mteegfx.itch.io/grunio2
Platform: NES
The ROM is the .zip file inside the downloadable file "Gruniozerca 2 - The Great Cavy Rescue!.zip".

Gruniożerca 3: The Great Cavy Clean-up!: https://mteegfx.itch.io/grunio3
Platform: NES
The ROM is the .nes file inside the downloadable .zip file.

MW ULTRA: https://protovision.itch.io/mw-ultra
Platform: Commodore 64 & C64 Mini/Maxi
I don't own the game, but it very likely comes with emulatable files for the C64 and C64 Mini/Maxi, likely in the download option "MW ULTRA (C64 files only)".

Galencia for the C64: https://galencia.itch.io/galencia
Platform: Commodore 64
I don't own the game yet so I can't check the files, but it seems it comes with a C64 ROM too.

Neutron: https://sarahjaneavory.itch.io/neutron
Platform: Commodore 64 & C64 Mini/Maxi
Includes 2 ROMs, the .crt and .d64 files (not sure what's the difference between them).

Santron: https://sarahjaneavory.itch.io/santron
Platform: Commodore 64
Includes 2 ROMs, the .prg and .d64 files (not sure what's the difference between them).

Zeta Wing: https://sarahjaneavory.itch.io/zeta-wing
Platform: Commodore 64 & C64 Mini/Maxi
Includes 3 versions of the ROMs. See which fits your needs the most. The ROMs are available in the formats .tap, .prg and .crt.

Heroes & Cowards – The Pentagram of Power: https://protovision.itch.io/heroes-cowards
Platform: Commodore 64 & C64 Mini/Maxi
I don't own the game, but it very likely comes with emulatable files in the download options "Heroes & Cowards (C64).zip" and "Heroes and Cowards (Mini and Maxi files)".

The Camp - Caravan Edition: https://protovision.itch.io/the-camp
Platform: Commodore 64
I don't own the game, but it seems it comes with C64 ROMs, likely in the files with "D64" in the name. Also seems to come with both German and English versions.

Jim Slim: https://protovision.itch.io/jim-slim
Platform: Commodore 64 & C64 Mini/Maxi
I don't own the game, but it seems it comes with emulatable files, likely in the download options with "D64" and "Mini and Maxi files" in the name.

Advanced Space Battle: https://protovision.itch.io/advanced-space-battle
Platform: Commodore 64 & C64 Mini/Maxi
I don't own the game, but it seems it comes with emulatable files, likely in the download options with "D64" and "Mini and Maxi files" in the name.

Stroke World: https://protovision.itch.io/stroke-world
Platform: Commodore 64 & C64 Mini/Maxi
I don't own the game, but it seems it comes with emulatable files, likely in the download options with "D64" and "Mini and Maxi files" in the name.

It's Magic: https://protovision.itch.io/its-magic
Platform: Commodore 64 & C64 Mini/Maxi
I don't own the game, but it seems it comes with emulatable files, likely in the download options with "D64" and "Mini and Maxi files" in the name.

It's Magic 2: https://protovision.itch.io/its-magic-2
Platform: Commodore 64 & C64 Mini/Maxi
I don't own the game, but it seems it comes with emulatable files, likely in the download options with "D64" and "Mini and Maxi files" in the name.

Ice Guys: https://protovision.itch.io/ice-guys
Platform: Commodore 64 & C64 Mini/Maxi
I don't own the game, but it seems it comes with emulatable files, likely in the download options with "D64" and "Mini and Maxi files" in the name.

Tanks 3000: https://protovision.itch.io/tanks-3000
Platform: Commodore 64 & C64 Mini/Maxi
I don't own the game, but it seems it comes with emulatable files, likely in the download options with "D64" and "Mini and Maxi files" in the name.

Team Patrol: https://protovision.itch.io/team-patrol
Platform: Commodore 64
Includes both a demo and a full release. Both .d64 files.

Leisure Suit Leo 2 - The Secret of Maniac Island: https://protovision.itch.io/english-leisure-suit-leo-2
Platform: Commodore 64 & C64 Mini/Maxi
I don't own the game, but it seems it comes with emulatable files, likely in the download options with "D64" and "Mini and Maxi files" in the name. Also seems to come with both German and English versions.

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Another anthology:
Action 53 Volume One Function 16: https://action53.itch.io/vol1
Platform: NES
Multiple games included inside the ROM. The ROM is the .nes file inside the downloadable .zip file.
Games/Tools included in the ROM:

NES15 by Mathew Brenaman
TapeDump by Chris Covell
Driar by David Eriksson and Stefan Adolfsson
Streemerz (after Mr. Podunkian) by Faux Game Co.
Forehead Block Guy by Joshua Hoffman
I Wanna Flip the Sky by Tom Livak
MineShaft by Nioreh
Munchie Attack by Joe Parsell
LAN Master by Shiru
Lawn Mower by Shiru
Zooming Secretary (with PinWizz) by Shiru
NES Virus Cleaner by Sly Dog Studios
Slappin' by Michael Swanson
Concentration Room by Damian Yerrick
Music Toy: Axe by Damian Yerrick
Russian Roulette by Damian Yerrick
Thwaite by Damian Yerrick
Zapper Calibration by Damian Yerrick
ZapPing by Damian Yerrick
Pogo Cats by Yggi

You can probably find most of individual ROMs on either the links in the anthology's page, or at http://forums.nesdev.com/
Sorry, but can't go digging for their individual versions right now.

VictimRLSH

Some Vic-20 (VICE) games on Github

https://github.com/theflyingape/omega-fury/releases/tag/final It's hard to believe that as incredible as the vic-20 version of Omega Race was, it was apparently improved upon.

https://github.com/theflyingape/berzerk-mmx/releases/tag/final A berzerk clone that actually includes the voices!

There are a HUGE number of free and commercial games available from the Vic-20 DENIAL forum, but the proprietor wishes all links to the site to be to the main page. http://sleepingelephant.com/denial/ To find the vic-20 goodies navigate to Forum->Announcement Board. From there, there are threads for new vic-20 releases for each year from 2008 to the present. Many are free.

Folly

@victimrlsh

I tried your games in "VICE standalone" and couldn't directly play them.
I think more people will have the same problem if they try.
I made a small animation for the most important settings you have to do.
( Menu = F12 )

themazingness

Regarding the 50 ROMS from Intellivision Lives!, for some reason the games play fine in RetroArch in Windows 10 but none seem to work on my Pi. I'd be surprised if there isn't a solution, but I haven't found it yet.

Edit: The solution is renaming the BIOS files to all lowercase. They are all uppercase in the PC collection.

Auster

Kumi-Daiko Beatoff 64: https://zhamul.itch.io/kumi-daiko-beatoff-64
Platform: Nintendo 64
The ROM is the .n64 file inside the .zip file that can be downloaded from the option "Kumi-Daiko Beatoff 64 [N64 Rom]".

Siikasaurus: https://zhamul.itch.io/siikasaurus
Platform: PS1/PSX
The ROM are the .cue and .bin files inside the downloadable .zip file.

Sweethearts: https://zhamul.itch.io/sweethearts
Platform: NES
The ROM is the downloadable .nes file.

Tag: https://zhamul.itch.io/tag
Platform: Sega Genesis/Mega Drive
The ROM is the .bin file inside the downloadable .zip file.

Duel: https://zhamul.itch.io/duel
Platform: Sega Genesis/Mega Drive
The ROM is the .bin file inside the downloadable .zip file.

Double Cooked: https://zhamul.itch.io/double-cooked
Platform: Sega Genesis/Mega Drive
Has 2 updates available, v 1.0 and v 1.1, each properly marked in the download options. The ROMs are the .bin files inside each downloadable .zip file.

Heart Knight: https://zhamul.itch.io/heart-knight
Platform: GameBoy
The ROM is the .gb file inside the .zip file that can be downloaded from the option "HeartKnight.zip [GB Rom]".

Woolball's backyard: https://zhamul.itch.io/woolballs-backyard
Platform: GameBoy
The ROM is the .gb file inside the .zip file that can be downloaded from the option "Woolball [Gameboy ROM]".

Poopster: https://zhamul.itch.io/poopster
Platform: GameBoy
The ROM is the .gb file inside the .zip file that can be downloaded from the option "Poopster [Game Boy Rom]".

Overseer: https://zhamul.itch.io/overseer
Platform: Vectrex
The ROM is the .bin file inside the .zip file that can be downloaded from the option "Overseer [Vectrex bin]".

Arcade Legend: https://zhamul.itch.io/arcade-legend
Platform: GameBoy
The ROM is the .gb file inside the .zip file that can be downloaded from the option "Arcade Legend [Game Boy Rom]".

Hyper speed: https://zhamul.itch.io/hyper-speed
Platform: Vectrex
The ROM is the .bin file inside the .zip file that can be downloaded from the option "HyperSpeed [Vectrex bin]".

Telocation: Gemini: https://jtn191.itch.io/telocation-gemini
Platform: Nintendo 64
The ROM is the downloadable .n64 file.

The Last Amazon Trilogy: https://psytronik.itch.io/amazon
Platform: Commodore 64 & C64 Mini/Maxi
Includes multiple ROMs of the series. The ROMs are the .tap, .prg and .d64 files inside the downloadable .zip file.

[German] Crazy News: https://protovision.itch.io/german-crazy-news
Platform: Commodore 64
I don't own the game, but according to the store page, it very likely comes with a C64 ROM. Also, the game appears to be only in German.

Metal Dust: https://protovision.itch.io/metal-dust-c64-supercpu
Platform: Commodore 64 SuperCPU
I don't own the game, but according to the store page, it can be played with emulators, so it comes with a ROM.

Bomb Mania: https://protovision.itch.io/bomb-mania
Platform: Commodore 64 & C64 Mini/Maxi
I don't own the game, but according to the store page, it very likely comes with emulatable files for the C64 and the C64 Mini/Maxi.

Hockey Mania: https://protovision.itch.io/hockey-mania
Platform: Commodore 64 & C64 Mini/Maxi
I don't own the game, but according to the store page, it very likely comes with emulatable files for the C64 and the C64 Mini/Maxi.

Auster

Father's Day: https://quantumsheep.itch.io/fathers-day
Platform: ZX Spectrum
Has 2 versions which are explained in the page's description.
The ROMs are the .tap files inside the downloadable .zip files.

Also includes the source code (the .xml file), which supposedly can be edited and/or compiled to other platforms, as listed in the Lantern engine's site: Amstrad CPC64, Apple IIe, Commodore 64, CP/M, IBM PC/XT, TRS-80 1/3/4, ZX Spectrum and Linux.
But good luck using the engine, as there's hardly anything online about it, leaving a lot to figure out (and I couldn't even make it work natively on Linux).

ts-x

@themazingness said in Where to (legally) acquire content to play on RetroPie:

Regarding the 50 ROMS from Intellivision Lives!, for some reason the games play fine in RetroArch in Windows 10 but none seem to work on my Pi. I'd be surprised if there isn't a solution, but I haven't found it yet.

I can confirm that all ROMS from Intellivision Lives!, as well as those from Intellivision Rocks! and Intellivision Greatest Hits all play fine via jzintv. Not sure about freeintv but I’m assuming there’s a way to get them to work with that core as well.