Warface!

Team Fortress 2 (TF2) is the sequel to the game that put class-based, multiplayer team warfare on the map. One of the most popular online action games of all time, TF2 delivers constant free updates including new game modes, maps, equipment and, most importantly, hats.

Cube 2: Sauerbraten is a free multiplayer/singleplayer first person shooter, built as a major redesign of the Cube FPS.

Urban Terror started as a realism based "total conversion" mod for Quake III Arena. Nowadays, Urban Terror is played using the free, stand-alone, ioquake3 engine modified, which doesn't require Quake III Arena, in addition to being an add-on to id Software's Quake III Arena.

Squad is a 50 vs 50 multiplayer first-person shooter that aims to capture combat realism through communication and teamplay, emphasizing both strong squad cohesion mechanics as well as larger scale coordination, tactics and planning. It features large open maps, vehicle-based combined arms gameplay, and player-constructed bases to create a heart-thumping, visceral gaming experience which mixes organized tactical multi-squad planning with split second decision-making in real-world scale firefights. »

Incessant warfare in Tarkov has sparked massive panic; the local population has fled the city, but those who stayed are looking to improve their fortunes at the expense of others. Well-armed gangs started the redivision of the city. Tarkov is separated by unseen borders, controlled by different groups.