Garry's Mod Trouble in Terrorist Town Servers

What is a Garry's Mod TTT server?

A social deduction mode. A minority of players are secretly traitors and have to kill everyone else without being identified; innocents have to work out who they are from behaviour and bodies. Detectives get equipment that can confirm a corpse's role.

Rounds are short and most of the game is conversation — accusations, alibis, someone getting shot for standing in the wrong place. Killing an innocent on a hunch is punished, so servers vary a lot in how strictly they police it. Look for one with active admins; TTT falls apart quickly without them.

This is a short list — 3 servers on Garry's Mod at the moment. The full Garry's Mod list is a better place to start if none of these fit.