A guy I like a lot that very few do---Sven Ottke. He kept those hands and arms up high the whole fight. Extremely hard to penetrate & add to it his boxing radar.
Mike McCallum, Gennady Golovkin, George Foreman, Muhammad Ali, James Toney. Edit: Marvin Hagler, Michael Spinks.
Winky Wright, Marlon Starling, and Usyk all have great guards that can pick off most blows. Tough to penetrate.
Well, Joe Louis saw Max Baer as a c-blocker when they fought. In order to consummate his marriage asap, the Brown Bomber posted a consummate performance. Note to self: never get in the way of a horny Joe Louis.