Don't mistake Crawford "in the ring" and Crawford "out of the ring." Inside the ring he is all business and merciless. Outside he is great with the community, has actually gone to Africa multiple times with a former teacher to assist with getting small villages improved, and built a gym that he allows underprivileged youth to use for basketball, football and boxing training. He is quiet and soft spoken at boxing events and is more than willing to help with our local boxing programs
True there's only one Sweet Pea, just like how there's only one Ali and one Mayweather. Doesn't mean there aren't fighters that imitated or fought like them.
There's been plenty of fighters that took their style from another great fighter, whether they used it poorly or made good use of it. Back then there's been boxers trying to be like Ali such as Nino LaRocca, James Tillis, Howard Davis Jr., Naseem Hamed. Nowadays boxers are trying to be more like Mayweather with his shoulder roll technique.
My mistake, thought you were asking about what guys mimic Ali and Mayweather from my last response. If you were asking what fighters imitated or fought similar to Pernell there was already some good examples on this thread such as Moreno, Calderon, Farmer, etc. They're not an exact copy of Pernell but you can tell that they took some influences from his style.