I dont know much about Pbass but going from what I have kept with my Oscars I'd say: You should be super safe with Silver Dollars (of course) and for color you could also try a Firemouth and/or a Severum
As far as other options that may cause flaming I will tell you that I have succesfully kept Golden Gouramis as well as large Angelfish with oscars as well (12inch oscars and 4 to 6 inch Angels, Gouramis were full size around 4 inches) of course they will add quite a bit of color as well.