Towards the end of his career, commentators were calling Joe Louis the best boxer ever. But I think it was a much more controversial subject before Ali and especially SRR.
Basilio & Fulmer always skoffed when they heard the SRR "GOAT" title. They liked beating Ray up if they had the chance.
I didn't think there was one. The whole thing was bestowed on SRR because the so called " experts " of the day believed if both were the same size Sugar Ray had the beating of Joe. Hence the p4p best fighter in the world moniker.
A SRR famous quote when asked if he beat Joey Maxim would he go after Marciano?: "What, do you want to get me killed?"
George Dixon seems to have been named at some points, and I have heard Joe Gans's name thrown about. As others have said, it was a more controvertial subject.