Co-Op

Final Exam is a side-scroller video game developed by Mighty Rocket Studio. Up to 4 players can work together to survive the outbreak.

Revival of the NES classic beat 'em up with features such as four-player co-op and online play.

Homefront: The Revolution is an open-world first person shooter where you must lead the Resistance movement in guerrilla warfare against a superior military force. A living, breathing, open world responds to your actions – you and your Resistance Cell can inspire a rebellion on the streets and turn Occupation into Revolution, as oppressed civilians take up the fight. But your enemy has the advantage – superior technology, firepower, heavy armour and air support.

For Honor is an upcoming online action hack and slash video game in development by Ubisoft Montreal and set to be published by Ubisoft for Microsoft Windows, PlayStation 4, and Xbox One. It was announced at the 2015 Electronic Entertainment Expo. The game features a hand-to-hand combat system described as "The Art of Battle" by the developers and allows players to play the roles of historical soldiers such as medieval knights, samurai, and vikings within a Medieval fantasy setting.
Source:Wiki

The only aim in Rust is to survive. To do this you will need to overcome struggles such as hunger, thirst and cold. Build a fire. Build a shelter. Kill animals for meat. Protect yourself from other players, and kill them for meat. Create alliances with other players and form a town. Whatever it takes to survive.

Miscreated is a multiplayer online hardcore survival game set in a post-apocalyptic future. You will need to survive against mutants, players, and even mother nature herself.

As the lone survivor of a passenger jet crash, you find yourself in a mysterious forest battling to stay alive against a society of cannibalistic mutants. Build, explore, survive in this terrifying first person survival horror simulator.

Hybrid Wars lets you command and upgrade your own arsenal of futuristic mechs to take on wave after wave of enemy forces. Jump into a classic top-down shooter experience as you obliterate over 50 types of enemy and team up with friends to cause more mayhem. Harness an arsenal of diverse machines—tanks, robots, and helicopters—to rise to the top of the food chain. With 8 huge locations to explore, over 150 objectives to complete, and multiple game modes—from single player story to cooperative—Hybrid Wars immerses you in a future where those with the quickest wits and biggest guns survive.

Space Hulk: Deathwing is a First-Person Shooter experience based on Games Workshop's classic Space Hulk boardgame set in the universe of Warhammer 40,000. Space Hulk: Deathwing was developed on Unreal Engine 4, and offers you and up to three of your friends the chance to experience a desperate battle against Genestealers in the claustrophobic tunnels of a Space Hulk. You also gain skills, new abilities, and new equipment as you earn experience during missions.