You can't really count guys who were prolific amateurs. Lomanchenko didn't turn pro until he was 25, but winning 2 gold medals and having 400 or whatever fights is clearly a bit more impressive than the first few years and 20 odd fights of most good pros. It's especially true for Cubans, who literally couldn't turn pro until they defected, which could be very difficult and involve leaving everything to chance with no promoter, abandoning their family etc.