You'll be amazed of the list, here is a little list ->
Native Linux Ports
Quake The Offering (includes Quake, Scourge of Armagon, and Dissolution of Eternity)
Quake II
Quake II The Reckoning
Quake II Ground Zero
Quake III Arena
Eric's Ultimate Solitaire
Rise Of The Triad
Serious Sam The First Encounter
Serious Sam The Second Encounter
Soldier Of Fortune
Descent3
Railroad Tycoon II
SimCity 3000
Heretic II
Return To Castle Wolfenstein
Tactical Ops
Unreal (Or Unreal Gold or Unreal: Return To Napali)
Unreal Tournament
Unreal Tournament 2003
Rune
Hexen II
America's Army
Marble Blast
Medal Of Honor Allied Assault (Binary currently expired)
Savage
NeverwinterNights
Enemy Territory
Expand Your Choice .... LindowsOS