You cannot overlook Adamek. He has a spectacular chin plus very quick recovery time when he's hurt on his feet. He's been through 3 weight divisions, making 2 very large jumps in weight and was briefly down once in a war vs Paul Briggs.
JMM should be mentioned here as well. He's been down, but never out. He can certainly take some damage and still manage to work through the adversity.
Past - Lamotta,Chavez,Hagler,Chuvalo,Laporte, Tex Cobb,Villasana,Sanchez,Padilla,Basillio,Mccullough,Mercer,Jose Lopez,Tapia,Canizales,Qawi,Cob Castro,A Jimenez Present- Hopkins,G Johnson,Margartio,Mccall,Andrade,Vitali,Penalosa