Currently Online 
Super Smash Bros.
Of that series in particular: Melee, Brawl, and Wii U. Unfortunately, I haven't played local multiplayer for Smash Ultimate as much as I would like. And it's usually with just one person instead of a party.
Mario Kart is up there as well, and some of the better Mario Party games.
Lifetime Sales Predictions
Switch: 156 million (was 73, then 96, then 113 million, then 125 million, then 144 million, then 151 million)
PS5: 115 million (was 105 million) Xbox Series S/X: 48 million (was 60 million, then 67 million, then 57 million)
PS4: 120 mil (was 100 then 130 million, then 122 million) Xbox One: 51 mil (was 50 then 55 mil)
3DS: 75.5 mil (was 73, then 77 million)
"Let go your earthly tether, enter the void, empty and become wind." - Guru Laghima
