Board Game Arena

I'm part of a guild in an MMO who will do game night some nights, and our numbers usually range from like 10-20+. I know that format doesn't work well for board games per se, we've generally done Mafia since it's good for a lot of players and is very social. Perhaps we could split into 2 game rooms if those numbers are just too difficult to work with, but recommendations are appreciated.

One night ultimate werewolf runs up to 10 players and is a social deduction/bluff game that is great for that kind of player count.
Spyfall plays up to 8 players and requires better thinking on the part of the participants but is also a social deduction game but only one person is bluffing and the others are attempting to be "clear" without being "obvious".

Why Not make Some tournament with a quick and simple game for 4 persons?

The Love letter expansion can also be played with a lot of players, but i dont know exactly how Much.

I think the honest answer here is no. 6 Nimmt might be the best try but has a max of 10 players.
My vote would be colt express, but you'd need 2 tables of 6, or Possibly Saboteur.

Also, the tournament idea sounds good. Dragon Heart would fit the MMO theme best and it's very quick to play.