Kidney and Liver. It's not that they're the most common operations, it's that the risk of death is lower. Heart transplants happen more than you'd think, but if it goes wrong you usually die. Whereas...
cornea and kidney. (and skin)
1954: First successful kidney transplant by Joseph Murray (Boston, U.S.A.) 1966: First successful pancreas transplant by Richard Lillehei and William Kelly (Minnesota,...