Here are a few RPPCS from one of my favorite early leagues, the Northwestern League of 1905-1916:
1912 Seattle Giants
1915 Aberdeen Black Cats
Lots of Obak and Zee Nut players on these cards. The guy in the suit on the Aberdeen card is John Barnes, who appeared in the N172 set, and started pro ball in the Pacific Northwest in 1890.
Always looking to buy or trade for Seattle and Pacific Northwest postcards, and other goodies, if anyone is willing and able