Can you brush Tru color brand paints? Seems like they are the only maker of RR colors left.
They have a line a brushable paints. It covers most of the basic colors and also has many prototype colors as well. (Although for me, one color I would use isn't available in brushable last I checked. Thankfully I still have a supply from a prior manufacturer.)
FWIW, their paints will also handle down to -15 degrees F. Handy when you have to order it when you don't have an LHS.