It depends what genre you're looking for. There are a lot of *NIX games, and even more a lot of open source *NIX games [however, more are closed].
If you can name the genre I'm sure there'll be a lot from it.
And I can personally speak for War3/TFT working well in wine ^.^
From the top of my head before I head off to school:
- MMO: Regnum Online
FPS:
- Counter-Strike Clone: Assault Cube, enemy territory [+ mods]
- Quake-Based: Nexuiz, Tremulous, Quake, Alien [something], and a lot, lot more.
- Unreal tournament, Cold War
- Flight Sim: Flightgears, Gl-117, Thunder&Lightning, and some other game I can't remember the name to :/
- Stealth: Cold War
Those are all I can remember with corresponding categories that have native *NIX executables that aren't Tetris/Battleship clones and the like.