Which fighters are well-known for having unconventional but effective guards? E.g., Mayweather, Toney, or Burley's use of the Philly shell, Winky Wright's high guard, or Locche's practically non-existent, low hands guard.
Archie Moore and his cross-armed guard. Winky Wright and Marlon Starling used a very high guard. Kirkland Laing, Herol Graham, Naseem Hamed were known for their low guard.
Archie Moore, Ken Norton, Tim Witherspoon, George Foreman, Gene Fullmer, Bert Cooper, Joe Frazier and others using the crossgaurd, relatively speaking from the modern point of view. Sandy Saddlery and George Foreman with their intense use of rear hand in their long guards, leading to labeling them as converted from southpaws (true in Saddler's case.) Patterson, Torres, Tyson and their peekaboo.
Its best users always did. The Lock is just one part of the crossgaurd. It can be understood as 'armoring' the head movement, by limiting punch selection (such as folding against the uppercuts when dipping down) or when in a situation a more classic fighter would find himself out of position/out of spots to run. You can think of it as switching a doe for a ram, with Foreman being an examplary crossguard juggernaut, showing how it can be used to manipulate the initiative and tempo of the engagements against younger fighters.
For an up-and-comer, how about Ben Whittaker? He's the reincarnation of Locche, with a bit of Hamed thrown in for good measure. Hands often completely down and avoiding punches off his absurd reflexes.
No. Whitaker is an arrogant tosspot who raises my blood pressure every time I see him. Locche was one of the best defensive boxers of all time and a master at counter punching, Hamed's showboating was mostly limited to flashy head-movement and footwork. Whitaker just takes the **** out of journeymen and was getting tagged pretty regularly in his last fight.
Completely unproven and got nailed often by an average fighter in his last fight, his height enables him to lean back from shots.
I wouldn’t call Nicolino Locche a counter punching master for the same reason I wouldn’t call Wilfredo Benitez that because the efforts were evasive minded first and not offensive.
Taking everything on the gloves isn’t effective blocking and just stops you being knocked out some of the time.