Racing Stribes, The Derby Stallion, the newest one is Secretariat, and this website has many, many more.
Ebony, Midnight, Black Cherry, Storm, Freedom Rain (I personally just like that name).
A colt is a young male horse, a stallion is an adult male horse, a stud is a stallion that is used for breeding and a gelding is a male horse that has been gelded so he cant breed.
James if it is a boy... Sally if it is a girl...
oreo but when naming a horse think outside the box and find a weird name or an unused one like gipsy or paiten