Top games by current player count
Current Players Peak Today   Game
 
506,111 1,019,090   Dota 2
217,712 611,412   Counter-Strike: Global Offensive
82,906 113,617   XCOM 2
56,381 66,345   Team Fortress 2
46,992 57,491   Sid Meier's Civilization V
38,065 48,239   Garry's Mod
37,550 44,496   Fallout 4
34,400 49,957   ARK: Survival Evolved
33,510 52,394   Grand Theft Auto V
30,752 47,496   Rust

Steam Hardware & Software Survey
Steam Stats