At 175 Bob Foster was very durable; Arguello was teak tough at 126, 130 and 135. Panama Al Brown is perhaps the classic example IMO.
Manuel Medina was very durable. Went on too long and was eventually stopped a few times but in his pomp withstood some real punishment.
Most of Jose Ribalta's stoppage losses were of the TKO variety or past his prime, but he could take a beating and keep ticking. Watch the Tyson fight for example. Very tough.