E-Cards and R-Cards (Candy/Gum)
E-Cards and R-Cards are candy and gum issues. In general, E-Cards are earlier issues dating until around 1930 while R-Cards are after that time.
These issues were typically packaged with children’s products, such as candy, gum, or caramel. While tobacco cards were the primary issues of the early 1900s by the 1910s and 1920s, more candy companies were catching on to the popularity of sports cards among children.
Those issues, of course, paved the way for later sets, such as the Goudey and Topps issues, which became popular in the 1930s and 1950s.