Top games by current player count
Current Players Peak Today   Game
 
797,527 1,094,007   Dota 2
573,044 651,028   Counter-Strike: Global Offensive
129,408 130,183   XCOM 2
72,996 72,996   Sid Meier's Civilization V
70,141 79,396   Team Fortress 2
64,342 66,924   Football Manager 2016
62,858 64,544   Garry's Mod
58,456 59,358   ARK: Survival Evolved
57,532 57,532   Fallout 4
54,876 57,747   Rust

Steam Hardware & Software Survey
Steam Stats