A couple more corrections: Quarter Horses have all overo genes: frame, sabino, and splash and can be loudly colored. The APHA discontinued the crop out rule, so all QHs with an excess of white are still QHs now.
And Paints (I see the first response changed to pinto): Not every Paint is a pinto and not every pinto is a Paint. Pintos must have a white patter, Paints do not require it and they aren't just QHs with a white pattern because tobiano does not exist in QHs.
I just wanted to point out that 99% of Thoroughbreds that are registered as "roan" are actually gray, sabino, or rabicano. True roan did not originally exist in the breed, & now only exists in a handful of descendents of Catch A Bird, as a result of a genetic mutation.