Which fighters have looked like their careers where over only to comeback and achieve things people never dreamed they would?
Tsyzu v Phillips Mayweather v Castillo PAC v Morales 1 Ali v Frazier 1 Robinson v Bastillo Ottke v Mundine First that spring to mind
Klitschko was written off by a lot of people after getting KO'ed by Purrity, and later, Brewster. Certainly no one thought he would come back dominate for so long.
Klitschko I think. A really huge domination after being KO'ed coldly. About Jacobs ... yeah, but he got a comeback not only in boxing but in life.
I'd say Wlad when you factor in the magnitude of his comeback: a >10 year undefeated reign. Along with how low his low point was. I'm not as impressed by comebacks when a boxer just stops fighting then "comes back." I'm more impressed by how Wlad seemed to be exposed, dominated, inherently flawed, etc, and then managed to come back so strongly.
James Braddock the cinderella man had about 26 losses when he went on a winning streak and beat Max Baer for the heavyweight title. George Foreman took ten years off and then won the heavyweight title. Ali in his later career, three years off and the Frazier loss, beats Frazier then Foreman. Larry Holmes stayed in the top ten for about a decade after he lost the title. Ray Leonard retired for a couple of years before coming back to beat Hagler. Ray Robinson retired for a couple of years and became middleweight champ again beating Fullmer and Basilio. Acelino Freitas takes off five years, goes up four weight classes, beats ass. Eder Jofre lost the title to Harada, retired for a few years, came back and won it again. Vitali Klitschko took 4 years off then regained the title to reign another four years. Tony Thompson's post 40 year old career where he iced Price and Solis was pretty impressive too. After Tony Bellew got knocked out by Stevenson he avenges his loss to Cleverly, beats Makabu to pick up a cruiserweight title then knocks out heavyweight David Haye. Oh, and Vinny Pazienza's return to boxing after breaking his neck was impressive too.
Manny Pacquiao. Unbelievable comeback. Got one punch iced by the biggest steroid abuser in sports history and then came back to beat Rios, Bradley 2X, Algieri, IVayweather, and Vargas.
MAB. Lost back to back to Poison Jr Jones, won a few, lost a disputed decision to Morales, comeback to beat Hamed and Morales(disputed) before being blitzed by Pacman. When thought to be finished, managed to have good wins against Ayala, morales, peden, Juarez before losing a close fight to JMM and another decision loss to pacman. Great fighter who was able to reinvent himself a few times throughout.