Rank the top 20 baseball cards of all time. There may be others you'd select but this list includes some of the most popular and most important cards ever issued.
http://www.ranker.com/list/best-baseball-cards-of-all-time-v1/editor,
1909-11 T206 Sherry Magie Error
1933-34 Goudey Nap Lajoie
1909-11 T206 Joe Doyle NY Nat'l Variation
1934 Goudey Lou Gehrig #37
1914 Baltimore News Babe Ruth
1941 Play Ball Joe DiMaggio
1952 Topps Mickey Mantle
1909 T206 Honus Wagner
1954 Topps Hank Aaron
1955 Topps Roberto Clemente