The USRA steam engines can be painted for a large number of roads without having to go fantasy.
Oddly enough, they are fantasy paint schemes. (But at least they're not outrageously painted...) Only the Atlantic Coast Line, Baltimore & Ohio and Louisville & Nashville bought USRA Light Pacific's. Only other roads that bought what are known as "copies," purchased after the USRA was dissolved, were the Grand Trunk Western and Mobile and Ohio (merged later into the GM&O.)
No other roads bought USRA Light Pacific's or copies.
Now, the USRA Light Mikado: That was a locomotive purchased by a pretty good number of railroads.