Roach, the late steward and cus D'Amato. Sorry, I am not sure how many championship s held though. Also not sure if it indeed is these 3. Just saying my favourite s.
arcel, damatto, dundee, beristein, steward, futch, are all names that really knew their business. the rest is finding the right fighters that can take your direction all the way to the top. modern trainers, i like derrik james, robert garcia and eddy reynoso. different approaches but all produce results.
Im surprised no one has mentioned Angelo Dundee, Whitey Bimpstein (or whatever his name was, Sixto Escobar''s trainer), Jack Blackburn or Lou Duva. But Im glad you all remembered Emmanuel Steward. I met him and he was as humble and nice a person you will ever meet!