Leo Carillo, J Edward Bromberg, and Noah Beery are names most often cited.

It would have been interesting to see "Pancho" play Charlie Chan. Of course the PC police would have been all over that :)

A role that Toler was up for, but didn't get, was as Casper Gutman in the Bogie vesion of Maltese Falcon. Now, that would have been a study in contrast with Chan!