Some fighters retire with only a few fights, but manage to accomplish a ton in those fights. Among these types of people, is Sugar Ray Leonard. He is a multiple weightclass champion and in a span of 40 fights managed to become the welterweight, middleweight, and lightheavyweight champion of the world. Although his middleweight title bout was controversial, it was a win all the same and still counts on paper.
Another is Rocky Marciano. In only 49 fights he managed to beat 4 hall of famers, 2 were still very near their primes, 1 was in it, and the other was still a very game challenger, just long past his best. He still holds the record for the best winning percentage and the most fights. He had 49 wins, 0 lost, and 0 draws with 43 knockouts. That's an 88% KO rating, which is the highest out of any of the heavyweight champions.
Another is Rocky Marciano. In only 49 fights he managed to beat 4 hall of famers, 2 were still very near their primes, 1 was in it, and the other was still a very game challenger, just long past his best. He still holds the record for the best winning percentage and the most fights. He had 49 wins, 0 lost, and 0 draws with 43 knockouts. That's an 88% KO rating, which is the highest out of any of the heavyweight champions.