While they weren't single fights but "comebacks to the sport"

'Big' George Foreman - Came back after a long hiatus from the sport to become the oldest heavyweight Champion ever

'Dr. Ironfist' Vitali Klitschko - Came back after years away from the sport due to injury & dominated every single opponent he fought

'Will 'o the Wisp' Willie Pep - Came back after surviving a plane crash to continue to dominate