I'm sure this will be a very short list. Head to head using the original 8 divisions who were the guys that you are comfortable saying could hang with the all time top 10 in multiple divisions and why?
I'm assuming you mean the original divisions. There'd be loads if you accepted the ******* divisions. For guys I think could comfortable hang with elites at 3 of the original 8 divisions are: Ezzard Charles Roberto Duran Bob Fitzsimmons Jimmy McLarnin Tony Canzoneri Ismael Laguna Manny Pacquiao They stand out pretty predominantly. There's probably a 100 who could do it at two. Guys like Roy, Toney, Floyd, Greb, Tunney, Arguello, Jofre, Harada ect; would comprise that list.
Duran has done it. He hung well with Hagler and Leonard and did good stuff at lightweight and that’s three original divisions. I think an on Duran would give Monzon hell too plus others.
I think the yardstick for this subject is: Armstrong Duran Greb Langford Bob Fitzsimmons Ezzard Charles As has already been pointed out there are many more who could rumble in 3 divisions but I think these guys are the standard
Robinson Armstrong Barney Ross Dela Hoya Mayweather Pacquiao Hearns Leonard Duran Langford Argüello Benitez Gomez Roman González Lomachenko Marquez Roy Jones Nonito Donaire Hopkins Whitaker Morales Barrera Tapia James Toney Camacho Barrera Mikey Garcia Hasegawa Yaegashi And I guess Kazuto Ioka
If it's two original divisions you have a longish list. Three of the old divisions narrows it down hugely. That's like hanging with ATG flyweights bantams and feathers; feathers, lightweights and welters; welters, middles and light heavies. And then we're talking ATGs at those weights, Imagine fighting Robinson at welter, LaMotta or Zale at middle and then moving up to challenge Moore? @Reinhardt's list covers it for me, if it's three original weight classes and fighting ATGs in it. I'd just add Ismael Laguna as per @George Crowcroft suggestion. A top performer at bantam and lightweight; not sure if he did much at feather but competing so ably in the classes either side would suggest he could have. In fact it may have been his optimum weight class.
Can't think of a better answer than Robinson at Lightweight, Welterweight, and Middleweight. People seem to forget he started at Lightweight and picked up some very good wins at/around the weight early on.