The obvious one to me is mike mccallum but that man could do everything. I never seen a fighter who uses everything that he's ever been taught. Palomino is another favourite body puncher of mine. Sonny Liston and Randy Turpin threw the same type of right hand to the liver. The right to the liver or heart/left hook to the head is a simple, deadly combo
Smokin Joe. That was a brutal left hook to the body he threw. And that was the only thing he ever did w/ his right hand was to throw to the body with it. And he never missed. It just didn't have the sizzle of that lefthook of his, but he was extremely accurate with that right hand to the body. Joe's right hand to the body is the most accurate punch the division has seen. But > Ali's popularity, nobody pays much attention to the bodyshots and love those quick flurries upstairs instead. But Joe wasn't shoeshining to the body when he fought.
Toney vs Nunn was a clinic on how to use bodywork to slow down and stop a taller quicker headhunter. Ricky Hatton vs Jose Luis Castillo was hard to watch have taken a few liver shots in my day. Those inside hooks were brutal. Just an aside, I can almost always tell if someone has trained by how they react to watching body shots in a fight. Everyone cheers for head punches most untrained people don't really react to body work but those who have sparred and know what it feels like let out an audible groan at body work.