Horses may have many different colours. However, contrary to what many people believe, they are not entirely random. Mane properties are defined by a finite set of pretty well known genes. Let the machine spirit pick them for you!
Just like my hair-o-matic made untold ranks and files of troops look good, the mane-o-matic promises to do the same for noble mounts.
It randomly chooses mane colours out of a pool of some realistic, popular ones: