Fighters who survived brutal losses to comeback and maintain quality fighter status .. Lennox Lewis after looked to both McCall and Rahman Wlad after Sanders and Brewster Michael Nunn vs Toney Louis vs Schmeling 1 Johnson vs Choynski Marvin Johnson vs Matt Franklin Many , many more ...
Yaegashi did this twice. Duran is the definition of this idea. Although Tatsuyoshi's losses to Zaragoza weren't bad I doubt that people expected him to win a title after those wars.
Floyd Patterson immediately comes to mind with his devastating TKO by Ingo in 1959 and his one-round losses to Liston in 1962 and 63. He came back to have some of his finest victories in his post-title years and at the time of his last fight, in 1972, Ring Magazine had him listed as the #3 heavyweight contender behind champion Joe Frazier.
Donaire getting schooled by Rigo then KO’d by Walters, has actually done some really good stuff in recent years.
Hearns on multiple occasions Camacho Pazienza (While not in a boxing ring,a great comeback nevertheless) J.Jackson.
Diego Corrales got dismantled and wrecked by FMJ. 5 Knockdowns and didn't win a single round. Then got sent to prison right after for 14 months. If this happened in today's climate no way would his career have continued. He assaulted his 98 pound pregnant wife giving her a broken collarbone and ribs and a bruised spine. Corrales then moved up in weight winning more world titles eventually giving us the Castillo classic fight.
Glen the Road Warrior Johnson lost multiple heartbreaking decisions and was KO by BHOP at 160. In 2004 he beat Clinton Woods, Roy Jones and Antonio Tarver back to back to back to win a world title at 175 and Ring Magazine's fighter of the year.
Atleast Tyson after the Buster Douglas Ass whopping had the guts to come out to press conferences and in public and interviews and didn't cry, hide, avoid the media like Ronda Rousey