I'm trying to expand my library of classic game/game-inspired music. Any recommendations would be greatly appreciated. I'm including some music that I particularly enjoy for reference.
Instead of chiptune inspired music, how about music that inspired chiptune ? Yellow Magic Orchestra had an important impact (namely) on '80s/'90s era video game music. Here’s Rydeen (1979).
I don't know how "pure" you want your chiptunes to be, but for my money Master Boot Record is some of the best stuff out there. I would definitely say it's at the very least gaming inspired if not pure chiptunes, and it kicks all kinds of ass. They've done a lot of covers of classic game music - Bloody Tears is a great one, as well as their cover of the Doom theme. But I really love their original stuff too. Internet Protocol is a 10/10 album to me.
Slightly less chiptunes but still absolutely gaming inspired is their side project Keygen Church. Tenebre Rosso Sangue from the Ultrakill soundtrack is probably their best known track. It's sort of a chiptunes adjacent castlevania-metal vibe? It's hard to describe but it absolutely destroys.
Developer Konjak (Joakim Sandberg) did good work on the Noitu Love 2: Devolution soundtrack, which is a free download (zip file) from his website and is very chiptune. The actual link on the website's main page has an errant slash at the end that has to be deleted for the download to work. Some of the album can be found on YouTube if you want a preview.
Another banger chiptune to go for comes from Zircon and the work he did for the Demon Truck Soundtrack, especially The Devil's Mudflap. It's 16-bit Genesis goodness, and the game is pretty fun! Zircon's done stuff for several games and is generally an all-around musical badass.
If you want to combine chiptune with sea shanties The Longest Johns have an album that is all chip tune version of sea shanties. It's called Commodore 1864.
Crawl OST by Alex Yoder. All his other stuff is pretty good as well, but this one is my absolute favorite. Too bad he doesn't release stuff very often.