One of my favorite game soundtracks that I feel like nobody else has heard is the OST to Creepy Castle. It's all chiptune, with a variety of themes, mostly fantasy stuff, but there's some sci-fi and other stuff as well. Probably my favorite songs in the soundtrack are A Wispy Breeze and Checkmate!
Full soundtrack is here:
https://dopterra.bandcamp.com/album/creepy-castle-official-soundtrack