Steam Workshop::4 Player Co-op

Oficina Steam: BattleBlock Theater. These are the story levels created by The Behemoth, re-created in an arena playlist so they can be played co-optionally with 2 - 4 players. Keep in mind that these levels were designed for 2 players.

Steam Workshop::4 Player Coop Challenge map

Synergy on Steam

Police Stories on Steam

Multiplayer - Official Satisfactory Wiki

Steam Workshop::4 Player Co-op

Halo: The Master Chief Collection Local Splitscreen on PC. : r/localmultiplayergames

Biped on Steam

Steam Workshop::XCOM 2: Tactical Co-Op

Steam Workshop::Half-Life Co-op