A total of 45 games (+ all of their mods) are supported. Names in red require you to set your Steam profile to public:

America's Army 3
Arma: Combat Operations
Arma 2 (DayZ, etc.)
Arma 2: Operation Arrowhead
Battlefield 1942 (Desert Combat, etc.)
Battlefield 2
Battlefield 2142
Battlefield 3
Battlefield: Bad Company 2
Battlefield: Bad Company 2: Vietnam
Call of Duty: United Offensive
Call of Duty 2
Call of Duty 4: Modern Warfare
Call of Duty: Modern Warfare 3
Call of Duty: World at War
Counter-Strike: Global Offensive
Counter-Strike: Source

Crysis 2
Crysis Wars
Day of Defeat
Day of Defeat: Source
Doom 3
Garry's Mod
Enemy Territory: Quake Wars
Half Life 2: Deathmatch
Killing Floor

Minecraft (Version 1.9+ only)
Left 4 Dead
Left 4 Dead 2
Medal of Honor Warfighter
Natural Selection 2
Quake 2
Quake 3
Quake 4
Soldier of Fortune 2
Team Fortress 2
Team Fortress Classic

Unreal Tournament
Unreal Tournament 2004
Unreal Tournament 3
Wolfenstein Enemy Territory

All Source/Orangebox Modifications (PVK II, Synergy, Sourceforts, etc.)
All GoldSRC Modifications (Natural Selection, Sven Coop, etc.)

Note: If you play any of these games or mods and there is no server on the server list for it, then please ask the server host of server(s) you frequent to add their server to Capture The Prize.