Houseparty - Brining empathy to online communication.
Xonotic - Xonotic is a free (GPL), fast-paced first-person shooter that works on Windows, OS X and Linux.
Booyah - Video chat with up to 12 friends at the same time.
Quake - Quake is a series of first-person shooter video games released by id Software.
Heaps - Tinder with your friends. Party in a group.
Counter-Strike - Counter-Strike is a PC-exclusive FPS video game developed by Valve Corporation.