Steam Workshop::ttt sky island v2
OG map, a little on the smaller side. Lots of options for close range combat and long range combat. I've seen this map work well on 30 person servers before.
There's a few fun traitor traps (Freeze the elevator for 1 minute, make a portion of the bridge collapse) that can be used by traitors to restrict other player's movement around the map. I think this gameplay is complimented nicely by the counterplay a smart detective can do with the grappling hook.