Pfp, a given weight? Feel free to do it in no order if you don't like rating Hearts? Also if you feel it explan your definition of Heart to give some context, be my guest! I'm interested in seeing these lists. I expect to see a whole lotta HWs and Mexicans here.
We all know the usual suspects that will be mentioned here. So I would like to give major props to Miguel Canto (again). Against the Thai opponent Tacomroi Vibomchai, Canto lost a pint of his own blood, apparently, to still win a decision. Canto in general showed heart regularly, coming back from early career losses (in his first bout especially) and KO loss (third bout) to having a legendary career as maybe the greatest Flyweight ever. He was also nearly always outweighed and physically outmatched by his opponents, and showed amazing guile, heart and even turned his weakness into strength. Maybe he didn't have legendary wars (I think he had some exciting exchanges with other legends) but he was a courageous Mexican warrior regardless. Vibomchai bout here (this guys record is almost certainly incomplete; its very hard to believe a 1 - 1 opponent was chosen for a title defense at that point of Canto's career, after Shogi Oguma wins, and took him to 'SD'. He was also ranked 5th in the world by WBC. Alleged record was 32-2-2 and was Thai champion at Bantam). This content is protected
I'll do 3 lists, one at HW, one overall and some obscure mentions, all in no order. My definition of heart is pretty much trying to overcome adversity at all costs, even without success. Being successful at overcoming obstacles is what separates good fighters from great ones, and is a different thing than heart. So without further ado! This content is protected Saad Muhammad Bobby Chacon Arturo Gatti Little Red Julio Cesar Chavez Lupe Pintor Henry Armstrong Jung Koo Chang Fighting Harada Barney Ross This content is protected Muhammad Ali Joe Frazier Evander Holyfield Larry Holmes Floyd Patterson Rocky Marciano Joe Louis Jack Dempsey Corrie Sanders Ezzard Charles This content is protected Johnny Owen should be on everyone's list. but I have a feeling we will be scarcely mentioned, but he went out-out on his shield and should be remembered for his heart to the end. I mentioned Chacon above, but the rest of the Fab 4 deserve mentions as well. Navarrete, Limon and Boza. Joey Maxim, his style was quite possibly the actual inspiration for the rope a dope, sit back and let them tire, then go on your own offence. He built his career, for the most part, on toughness and heart, and is the reason why he holds his greatest win. Stanley Ketchel was a man with no fear, and an unbreakable will. We all know this obviously, but I doubt he'll get mentioned much. Marvin Johnson, this guy went tooth and nail with everyone. He took punishment and always made an effort to get up, even if his whiskers permitted otherwise. He is one of my favourites tho, so I'm probably biased.
For me though, really, it's Joey Hughes. The guy shouldn't have ever boxed with his disability (can't use right arm properly, even his hand), much less become a top class European boxer (and should be the intercontinental and British champ IMO). He shows the true spirit of boxing and never gives up. He also has a devestating left! He is an inspiration to me as a fighter and a man, and I'm glad I've met him.
Marvin Hagler, he had the mental game sorted. Inter graded it into his training as well. Holyfield definitely had the heart and mentality also.
Marciano overcame pretty much every obstacle life could throw at him, an undefeated spirit in and out of the ring Louis doesn't he enough appreciation for his heart imo. He always fought to the bitter end even when he was depressed from crippling debt and ring lorned against a raging prime Marciano. I'm sure it baffled many as to why he got up from that left hook. He got up against so many opponents. Buddy Baer, Tony Galento, James J Braddock, etc. No wonder he was like a superhero. And the problems he had outside of boxing also show his enormous heart.
Already mentioned but another endorsement for Barney Ross. Maybe there have been fighters as tough as him, but not tougher.
Great list Robert but you left out the King of Kings in the heart dept. Stan Jonathon. He gave up 20 - 40 pounds in every fight but he took on EVERYONE and held his own