Top games by current player count
Current Players Peak Today   Game
 
604,124 1,137,360   Dota 2
272,062 689,174   Counter-Strike: Global Offensive
60,835 81,022   Team Fortress 2
55,118 73,327   Sid Meier's Civilization V
53,562 75,742   XCOM 2
45,818 64,738   Garry's Mod
44,292 62,394   ARK: Survival Evolved
40,490 52,548   Fallout 4
37,503 58,403   Rust
36,016 73,217   Grand Theft Auto V

Steam Hardware & Software Survey
Steam Stats