If you haven’t already, check out the baseball books available at the Internet Archive. In the 1900s and 1910s Spalding published a number of guides for local city baseball scenes, and the Internet Archive has volumes for Denver, Cleveland, Chicago, and New York.
In particular, the 1905 Chicago Amateur Base Ball Annual and Inter-City Baseball Association Year Book is a treasure trove for anyone interested in semi-pro and independent professional baseball in that era. There are team photographs of well-known semi-pro clubs like the West Ends, Gunthers, Spaldings, and All-Chicagos. And, right in the middle of all these white teams, there is this photo of the 1905 Leland Giants: