Xonotic - Xonotic is a free (GPL), fast-paced first-person shooter that works on Windows, OS X and Linux.
Rust Game - Rust’s world is harsh. The environment is not kind. Bears and wolves will chase and kill you. Falling from a height will kill you. Being exposed to radiation for an extended period will kill you. Starving will kill you. Being cold will kill you.
Quake - Quake is a series of first-person shooter video games released by id Software.
Apex Legends - A free, squad-based battle royale
Counter-Strike - Counter-Strike is a PC-exclusive FPS video game developed by Valve Corporation.
Fortnite Battle Royale - Fortnite Battle Royale is 2017, Free to Play, Battle Royale video game developed and published by Epic Games.