In no particular order
Jem Mace. First man to apply the sweet science to pugilistic endeavor and beat the piss out of much larger men in the process.
John Douglas or the 9th Marquees of Queensbury. Although penned by John Graham Chambers his stamp of approval changed boxing from a grappling circus like act to what we see today.
Nat Fleischer. Ring founder and incredible historian
Ray Arcel and Whitey Birmstein The Tag team trainers. Love Whitey’s famous quote. “Show me a fighter that is undefeated and I’ll show you a fighter that hasn’t fought anybody.
John L Sullivan. Pure pioneer. Held the bareknuckle title before gloves and then won it with them.
Tex Rickard
Ali
Ray Leonard. First 100 million dollar earner and for better or for worse changed the face of prize fighting.
Sulaiman. For all the wrong reasons starting with the creation of 17 divisions.


I’d throw Poverty in the mix if it were a person.