The criteria is that the fighters were at a similiar weight in the same time frame.
My 5 are

Kostya Tszyu v Shane Mosely 140 in 1999
Salvador Sanchez v Alexis Arguello 130 in 1981
Aaron Pryor v Sugar Ray Leonard 147 in 1980
Joe Calzaghe v Roy Jones 168 in 1997
Felix Trinidad v Shane Mosely 147 in 2000

There are so many more. Can u name a few?