Hylics 1 & 2. There's actually a sorta sleeper cult around the games where it seems like a lot of people know of them or have played them, but no one ever talks about them. Pretty standard action-rpg but everything's claymation. Oh, and the second game changes genre multiple times.

Cruelty Squad. Amazing immersive sim. Looks like trash, best gameplay I've encountered in a while. That game goes hard.

Bomb Rush Cyberfunk. I thought this was more popular, however considering how many people give me a "what's that" when I mention it, it makes me think it wasn't as popular as I thought. It's a very well made spiritual successor to Jet Set Radio Future. Even has JSRF's composer on a few tracks.

QT deserves more eyes on it for being an incredibly cute and wholesome parody of PT. There's a free "demo" version on Itch.io, and if you like that then I'd highly recommend buying the full version on Steam.

E.Y.E. Divine Cybermancy. This game is... hm. Basically it started off life as a Warhammer 40k game, but got released as something else due to the studio failing to secure the licenses they needed for WH40K. It's a much older indie game from back when Valve had standards regarding what made it onto steam. It's also kinda special because it's one of the few times the Source engine was used commercially outside Valve. It's also pretty jank, but overall pretty fun. It's got some pretty decent RPG mechanics on top of a first person shooter, complete with classes. You can hack basically anything but also anything can hack back. A door can hack you.