The genre of fighter you refer to cannot be profiled as an athlete.
Charles Bronson, Lenny McClean, John L. Sullivan, whoever you wish to mention; they were not athletes who decided to pursue a goal and become hard, they were products of their environment and earned notoriety not because they excelled but because they survived their origins.
Most didnt train; they fought as it was their method of survival.
There were no supplements; they ate what they could, when they could.
In times of success they feasted and in times of poverty they had famnine.
From the past we are left with the icons of giants.
In a time without weight divisions and in sport void of scientific conditioning, being big was a terrific and often deciding advantage. There were exceptions - such as Tom Molineaux - but generally the Bigger guys won and won their place in history.
The closest modern parallel is that of native Muay THai fighters.
They are brought up in a sport with poor equipment, poor nutrition and are held in little regard, as for every fighter there are five, ten, a hundred more willing to take their place.
This inspires a system where young fighters tear themselves apart in training and competition with little regard for the consequences of their self negligence.
Internationally we see the creme de la creme; individuals such as Samart Payakaroon. But how many tough guys did he beat on his way up? Iron sharpens iron; how many brutal wars had he to endure before he reached his prime. And how many others fell at his feet, because they were second best.
The men you mentioned never took any supplements. The hardest guys in the word then and now came from poverty- they didnt have nutrition. They didnt have and structured or educated training. Maybe they developed by osmosis. But more likely, they were gentically exceptional individuals who endured life's hardships & fought not because they had aspirations or dreams, but because they had no other means of employment.
So please I implore of you train smart and dont train to be tough.
Not only is it a proven fact that smart beats tough, but with modern training, nutrition, science and knowledge you can be stronger, faster, look better while sustaining much less damage.
The very best of luck.