Almost any game will work under Proton. If you want to be sure, check ProtonDB before you buy.

The main exceptions are competitive multiplayer games (like Valorant) that use rootkit anticheat software, but that’s probably for the best.

I’m a multiplayer guy so I’m playing dota 2 and guild wars 2. But any valve game (portal, half life 2, tf2, counter strike) .
Other games that I played previously and can recommend:
Factorio, chivalry 2, Elite Dangerous, Truck simulators, Grim Dawn, Horizon zero dawn, Kingdom come.
For more, look into https://www.protondb.com/

These days there are games and launchers to avoid instead of choose, giving you a wide pool of selection. Just pick whatever you want to play and check these 2 sites: protondb.com (for Steam games) areweanticheatyet.com (for multiplayer games)

I just finished Sekiro, worked flawlessly. Currently replaying Hades without issue. I’ve been gaming on PopOS with an 3080 for at least 18 months and its my only workstation. I don’t even have a dualboot to Windows

I play all my game thru steam proton or lutris

I am actively playing Warframe, Planetside 2, Deep Rock Galactic, Darktide, Elden Ring, Team Fortress 2, and Minecraft (through Prism launcher flatpak)

The only game that does not work that i wish did is Vermintide 2.

You should be asking what games don’t work on Linux at this point. I’m not even joking.