7. "Rocket League" (2015, Psyonix, for Linux, Nintendo Switch, OS X, PlayStation 4, Windows and Xbox One)
"Monster truck soccer" sounds like a novelty, like shovelware — not like one of the most reliably fun multiplayer games of the decade. But "Rocket League" was just that. It's also the multiplayer game I still return to most, even several years after its release. With a control scheme you can master in seconds but physics you couldn't map with a Ph.D., plus frictionless matchmaking, it's an endlessly fascinating arena for teamwork in the face of chaos. All these games later, every goal still feels like a triumph.