Alexis Arguello. Good counter puncher. Controlled aggression, tries to pressure opponent into punching back so as to make openings and catch opponent coming in.
Joe Gans and Alexis Arguello tick certain boxes but nobody else had that stealthy posture of holding up the gloves like he was balancing large cannon balls on top of his hands and shuffling around like he was on ice. It's that 'stealthy' aspect about Joe Louis that made him so distinct.
Coley Wallace ! (i thought i would say it before someone else did ! ) Coley alsobeat Marciano in the Ametuers as i recall.
Currentely Juan Guzman reminds me of Joe Louis, although he doesn't throw Joe Louis-style combinations often enough for my liking. As he improves I think he'll resemble the Brown Bomber more and more. David Haye is also a counter-puncher who often has his hands low, has fast hands and has a lot of power. His career so far also has shades of Joe Louis's as well: an advertisement for putting prospects in with dangerous opponents early to force them to learn tough lessons.