It's quite rare but here are few names: Jercey Joe Walcott Archie Moore Henry Cooper Wladimir Klitschko Who else would you name?
OK, forgive me, but Patterson came immediately to mind. One could argue that he was a better HW AFTER the two Sonny blowouts, though he, obviously, was mismanaged in his first reign. Most of his 'losses' after Sonny were his OWN undoing. Should have run the table twice against Quarry and against Ellis. Monzon and Valdez also come to mind though Carlos rose to the top much sooner whereas Rodrigo turned pro in 1962 at the age of 16 and didn't come 'Stateside' until the early 70's. People tend to ignore the protractive wars fighters waged in their younger days. Jersey Joe also comes to mind. I've missed a few I'm sure.
I'd say his peak performance was the KO of Johansson in 1960. He looked pretty good the first time he won the title too, against Moore in 1956.
A few modern ones Johnny Nelson Guillermo Jones Juan Manuel Marquez Jose Luis Castillo Orlando Salido Marcos Maidana is arguable Amir Khan is also arguable Peter Quillin could be another one to come, he's just gone into his 11th year as a pro Israel Vazsquez