Unusual Coats on Thoroughbred Horses

It used to be that all thoroughbred horses in the stud book were given few coat colors - chestnut, bay, brown, black, or grey.  Of course horses have many different coat colors, but those were the ones the thoroughbred owners and breeders used.  Due to cross-breedings, we now have many thoroughbreds of color.  Their are palominos, a few white, many roans, a few with large white markings (like pintos), and five brindles...