what 2 boxers no matter what seem to always pop up next to eachother on ATG lists ? barrera and morales is an obvious one to start
wlad and vlad... lol on a serious note, Lucas Matthyess and Marcos Maidana, just cuz they wont fight each other (yet)
Walcott and Ezzard, as Heavyweights (obviously Ezzard's greatness as a LHW sets him apart, but solely for the HW division).
Ted "Kid" Lewis and Jack Britton Sam McVey and Joe Jeanette Zora Folley and Eddie Machen Ezzard Charles and Archie Moore at one point, but in recent years Charles seems to get a lot more credit