"Skewbald" and "Piebald".  Weird names for horse colors but many of you  overseas use the terms, so you know what they are.  For us North Americans:  A Skewbald is a pinto or paint who is any color and white, except BLACK.  A Piebald is a black and white horse.

 

"Brindle"  A horse who may or may not carry the Dun Factor gene who goes beyond a dun to the entire body being covered with tear drops and/or zebra striping, including the back and barrel of the horse.  Most often seen in cattle and dogs.  Very rare.

 

"Mettalic Sheen"  Although not a horse color in the sense of the word, it is one worth mentioning.  Known only in one breed of horse.  The Russian bred "Akhal-Teke"  The skin is thin, the hair is SILKY and the mane and tail are spars.  Several colors are possible but the most common are bay, black, dun, chestnut. gray and palomino.  A distinctive feature is the pronounced METTALIC SHEEN, a glossy golden polish overlaying the basic coat color.  Awesome.

 

"Cremello" versus "Perlino".  Quoting the Cremello and Perlino Education Association:  Cremellos have white manes and tails, while Perlinos have golden hued manes, tails and points.  Both can have white markings, dappling and shadowing. 

 

"Albinos".  The true Albino does not exist.  There are a few that come close but careful research will show slight traces of Pigmentation somewhere on the skin and Pigmentation in their eyes.  A TRUE Albino would be without any Pigmentation in both his skin and his eyes.  There is no documented cases on record of a true Albino.  Or at least one that survived past foaling, to be studied and recorded.  Since, in general, it's a genetic flaw, it would not be an attribute.  A true Albino with absolutely no Pigmentation would be at the mercy of the sun's ultraviolet rays, presenting a great risk of such illnesses as skin and eye cancer.  Grey horses and white horses are already at a higher risk for such problems.  Quoted from Research Documents.