I'll just suggest the Prop Hunt server again, this being said, I havent done any research so I dont know how popular it is in CSGO.
I know people will say "prop hunt is for gmod" but I dont think it hurts to try since the only "new" ideia we have is another retakes server (wich I think is a good ideia)
Also, sometime ago in an admin meeting I suggested switching the Surf that we have right now for Timer. Why? Because Surf Timer doesnt require a lot of people to work, it always has people playing it, even it it's just 2 or 3.