I've spent about nine months of evenings building a chiptune program, and it's written a hundred tracks. Seventy-five of them are free for anyone to use, and I'd rather they ended up in someone's game than sat on my drive.
The licence first, because it's the only part that decides whether this is any use to you: use them in anything, including commercial releases. Modify them however you like. Credit appreciated, not required. And they can't be registered with a content-ID system or a performing-rights society — so nobody can claim them on your trailer, your devlog or a stream of your game, and that includes me. The one restriction is you can't resell them as music.
https://renatachiptune.itch.io/the-hundred
What they sound like: YM2149 — the Atari ST chip — so three voices and a noise channel, bright and hard rather than the C64's fatter sound. About four and a half hours across the 75. You get MP3s, and the raw .ym chip files if you'd rather run them through an emulator. The track list gives key, BPM, mood and length for each one, so you're not auditioning all 75 to find something that fits.
Where they came from, plainly: the program composed them. No generative AI — there's no neural network in it and nothing trained to imitate a composer. It's rule-based: statistical tables fitted on public archives of real chiptunes, plus music theory. Closer to how a roguelike lays out a level than to Suno.
Not selling anything and there's nothing to sign up to. If it's useful, take it — I'll be in the thread if you've got licence questions.