Pac
PBF
Martinez
Ward
W Klit

PBF and Pac have sailed weight divisions that other boxers just have not been able to do. They are almost always the msaller man in their fights.
Martinez also has conquered divisions and is fighting bigger/larger fighters in every match.
Ward is only a master of 1 division.
W Klit only has had to fight smaller foes for some time, but he has been winning so convincingly every fight... I think V Klit is better, technically, but he does not have the legs anymore.