My info says that there are three variations in size - 3 1/2" square, 3 1/2" with corners clipped, and 3" diameter. I have seen samples of all three of these shapes. My info also says 30 cards total and that baseball was 1-10 and A, B, D but there is a #31 Eller (football) that I have seen so not everything in my source is accurate. The checklist I have for baseball is A - Mays, B - Clemente, D - Mantle and 1-10 respectively, Kingman, Busby, Madlock, Burroughs, Simmons, Jones, Bell, Cash, Grote, and Lopes. This baseball checklist is accurate. Only basketball and football were also included. By the way, these were stickers.
Bruno
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Check my Profile page to see my 2023 Goals and my Lists of sets near completion (5 cards or less) or sets getting close (less than 100 cards missing and 75% complete).
https://www.tcdb.com/Forum.cfm/Page/B/ID/0/?MODE=VIEW&ThreadID=25745&C=0