6. Evander Holyfield
He holds the record of being the only four time world heavyweight champion. He has also been crowned as undisputed world champion in cruiserweight and heavyweight divisions. During his career, he reigned supreme over boxers such as Mike Tyson and George Foreman. He won 44 fights out of the total 57 he participated in during this career. Out of these, 29 were knock out wins for Holyfield.
