I have a number of 1/1 cards, mostly boxing. Here are some ones from various eras and sets that interest me:
1929 A's premium I picked up at the National. I think it was a soda mfg.:
1904 Sporting Life Munroe-Jeffries 2-sided cabinet card:
Coney Island Arcade Lou Gehrig:
Early 1930s Adam Hats Cards:
Red Dutton [Hockey HOFer]
H815 Adam Hats Jake LaMotta:
1920s W-Unc. Ty Cobb--I've seen a few others but they've all been 1/4 of a 4 on 1 Exhibit card, not a real strip card:
1960s Israeli Cassius Clay card [says "Cassius Clay [Boxing]" on the front.