It depends what you mean. I think by top contenders, it might be Maxie Rosenbloom (I have read he has 82 or 85 total wins over top 10 contenders, per The Boxing Librarian.) For HoFers, I’ve read it’s Harry Greb. Including newspaper decisions, he has 32-34 wins against 16 different hall of famers. Not sure about “prime”, but that’s somewhat subjective anyway.
Duran's is better. He fought the guys that Leonard did, except they were all in their prime. And Duran also had the best run ever at 135.
Grebb Robinson,recent times Fab Four with Duran in first place then argue over over three,JCC Roy Jones and his clean sweep all the way to Heavyweight Pac-Man Mayweather Cotto Marquez,tbh there is a lot of fighters over the year’s certainly worth a mention .
This would be better in the classic.. some of those fellas are boxing encyclopedias , a wealth of knowledge.
This always causes confusion. To me, resume is: who they fought, irrespective of the results. But to others, resume is: who they beat. To me, they’re completely separate things. That’s how I’ve been brought up. Guys like Charles, Greb and Moore have got great resumes. From the modern era, guys like Duran and Oscar. Floyd was a genius. But he never fought a prime great. So this is where it gets interesting to me. IMHO, Oscar has a better resume than Floyd. Oscar has a better resume, but Floyd had the better group of wins.