I meant like small addons. I Saw a server where, a detective would have a deerstalker, and would have new weapons, which arent normally included, On different servers!
You can add custom weapons, but you'll need to refer to BKU's custom weps making tutorial to make it compatible with ttt. There are specific things you need to alter in the (I'm guessing) shared.lua file so they can be bought or spawn with them or whatever. I haven't done this myself for my server but I'm sure that's how weapons go. As for other addons... what are you looking for? Admin addons?