. . . I'd recommend you take a special look at the R cards from the 1930s, which combine attractiveness and collectibility . . . and in particular, have a close look at the obvious 'crossover' sets for sportcard collectors. These allow you to build upon a base of knowledge you already have, and work on something a bit familiar but still different:
- R137 National Chicle Sky Birds
- R73 Goudey Indian Gum
- R114 US Caramel Presidents ( 'American Heroes Caramels' )