Insurgency - Take to the streets for intense close quarters combat, where a team's survival depends upon securing crucial strongholds and destroying enemy supply in this multiplayer and cooperative Source Engine based experience.
Call of Duty - Call of Duty is a first-person and third-person shooter series by Infinity Ward.
Hawken - Hawken is an Action, Free-to-play, FPS, Robots, Science-fiction, Tactical, Futuristic, MMO, Co-Op and Multiplayer video game created and published by Reloaded Games.
Xonotic - Xonotic is a free (GPL), fast-paced first-person shooter that works on Windows, OS X and Linux.
Warface - Warface - is a free online shooter with diverse PVP modes, exciting PVE missions, outstanding arsenal and millions of fans around the world!
Unreal Tournament - Unreal is a series of first-person shooter video games developed by Epic Games.