Top games by current player count
Current Players Peak Today   Game
 
586,213 1,127,317   Dota 2
393,389 657,283   Counter-Strike: Global Offensive
119,970 133,106   XCOM 2
68,208 75,066   Sid Meier's Civilization V
65,464 75,505   Football Manager 2016
58,536 77,861   Team Fortress 2
55,736 61,863   Fallout 4
53,936 62,485   ARK: Survival Evolved
51,215 64,976   Garry's Mod
48,204 61,467   Rust

Steam Hardware & Software Survey
Steam Stats