Full stop: I believe that 1955 Topps is one of the greatest baseball card designs in history. When I think of iconic, I think of this design, along with several others in the 1950’s and early 1960’s. it says a lot that Topps created an entire yearly set in Archives AND Heritage to recapture this aesthetic.
Beyond that, Clemente is one of the greatest baseball players of all time. The stories of his legend could fill a book. His life ended tragically. He never got the opportunity to have his life be fully celebrated in his post career.
Any number of his cards could fall under the “most iconic” banner, but I’ll go with his rookie card, which falls into the same issues as many cards of it’s era in terms of centering continunity, and many have simply faded over time.
Random Roberto Clemente Fact: Clemente led the National League in batting in 1964, 1965, and 1967. The only year among the four that he didn’t was 1966, when he won the NL MVP.