Black: is pretty strange, though not really rare. There is actually two types of black in horses; the non-fading black and the fading black. The fading black horses turns to brownish coat when exposed to sun for long hours, and the non-fading black horses, which has bluish-black shade doesn't turn to black.
Dark bay: brownish coat or seems like a very dark red hair. It is quite hard to differentiate from the seal brown. Other known names of this horse coat are: mahogany bay, black bay, brown bay.
Light bay: just lighter coating than the dark bay.
Liver chestnut: Sometimes referred to as brown. A dark brown coat of hair but lighter than the dark bay coat.
Chestnut: Almost close to red. The tail and mane are a bit brownish and lighter. Other variations of chesnut are liver, sorrel, or light.
Dun: has a yellowish coat with featured markings known as dun factors. It features a dark mane and tail colors, stripes along the back, upper legs and withers. Other colors are blue, red, yellow and bay or also known as zebra dun.
Roan: white hairs that are intermixed evenly across the body of the horse. They are usually grey and fades to lighter colors as it ages but its head are much darker and doesn't fade at all. Other variations are red, bay, and blue roans.
Palomino: a breed of horse that has a cream dilution gene which makes their colors turn yellow, tan, or gold. They also feature white mane and tail. Some other shades of palominos are cremello, very light but not white, chocolate but has a white mane and tail.
Piebald: Distinguishable by their black and white spotting. They are actually variations of Pinto; the term piebald is more known in the UK than the US.
Other variations of Pinto are: Piebald, Skewbald, Overo, Sabino, Tobiano, Tovero, Paint.
Gray: These breeds of horses have black skin but has a combination of white and black hairs across the body. They are brown with lighter skin but turns black as it ages. Other variations are Steel grey or salt-and-pepper, dapple, fleabitten, and rose grey.
Albino Horses: There are no albino horses that exist. They are born with unpigmented pink skin and white hairs.