Harry Greb was great

Yeah I think any list that doesn't have Greb in the top 5 ever is pretty much bogus.

 

He is the perfect enigma. His record reads like Fantasy Fiction, ridiculously active against top level opponents with amazing results up and down the weight divisions. The only surviving footage shows him goofing around and looking decidedly unimpressive. But it is not as though his record is merely very good, or even great. It's ridiculous and damn near unmatched in the history of the sport.