Large puffers would probably be ok, big wrasses, big angels, big tangs, can all potentially hang with a CT IMO, the bigger the tank the fewer issues of territory will occur....Believe it or not, there are several Triggers considered more aggressive than the CT...The Queen, Undulate, Titan, Blueline, and Yellowmargin are considered the meanest of the mean, these are the guys that typically need to be housed by themselves as they hit adulthood. I was at the Seattle Aquarium recently where they have a 15,000 gallon tank with over 100 fish, one being a 9 inch (which is not even half grown) Titan chasing everything it had a chance to, this included a slightly larger CT.