Which boxer would you choose to beat all the fighters in history?

True but it doesn't mean he can't rematch them and beat them the second time around

 

LL among the Giants...

Tyson, Holyfield, Louis, Ali, Foreman, Marciano, Dempsey and Jefferies among PROPER Sized Heavyweights, which I guess answers the question, as in theory they beat all other HWs and fighters in Divisions below.

the Badest men on the planet!

 

He was certainly too good for UK opposition

 

Sam Langford ...he could beat welterweights and heavyweights lol

 

That’s why I didn’t pick Lewis lol

 

I didn’t think he would ever lose

 

Really, I would take Wilde over Ali, because Ali might be a little weight drained making the Fly weight limit stay safe guys.

 

P4P, probably someone like Robinson, Armstrong, Duran, or Chavez would hold a staggeringly high number of wins. I don't think any boxer would go completely undefeated in a tournament against every single pro boxer, they'd all take a few L's no doubt.

H2H you'd probably need to be at least a cruiserweight or larger.

 

How many bites at the apple do my contenders get?

If they get endless rematches, any big puncher can do it. Given enough fights with each person they have to beat, even lesser skilled big hitters like Shavers and Wilder are going to pull off a KO win eventually.