This is a group of Baseball's Great Hall of Fame Exhibit postcards.  I cannot tell the age of these, but believe the Christy Mathewson, John McGraw, Rogers Hornsby, and Nap Lajoie are original 1948 cards.  The remaining have a brighter white color on the back and have a glossier sheen.  This group includes Rube Waddell, Honus Wagner, Walter Johnson, John McGraw, Connie Mack, George Sisler, and Eddie Collins.