Sunday LeagueG 20

Win Sunday League, Premier League!, Are You Trophy Thomas?, and L.O.G. Master by starting up a local multiplayer league, plugging in a second controller, setting the league to all games and races, and letting it run. You and the second controller will tie for first place every round.

L.O.G. Master will pop after the 7th DLC game finishes.
Are You Trophy Thomas? will pop after the 20th game.
Sunday League and Premier League! will pop at the conclusion of the 34th game.

This can be somewhat sped up by actively playing the games since the races will start a 30 second countdown once a racer finishes, and the race will finish when the timer expires.