Barotrauma should be able to take up to 16 players and if you as a group can get into this game then you will have a good laugh for a good amount of time.
Golf With Your Friends - up to 12 p. Simple game but getting hit by your friends ball right before scoring the hole kinda never gets old.
Any grand strategy will be able to host many players Civ, HoI, HoMaM, AoE, RoN, Stellaris, …