Without breaking out the Punnett squares and getting into the whole kit and caboodle about feline genetics and why cats come in pretty colors, here's a quick list of some of the rarer fur colors you might see some cats sporting. And, hey, while these cats aren't quite as fantastical as Lisa Frank's hot pink kitties, they're definitely as colorful.
If you're wondering why they call this color chocolate, look no further than the Havana Brown breed. These cats are one of the only breeds to have a "true chocolate" coat color. The "chocolate" color is actually a genetic mutation of the Black gene, causing the black to dilute to this delightful chocolate color. They also look great next to marshmallows and graham crackers.
Like Chocolate, Cinnamon is a dilution of the Black gene. Chocolate is recessive to Black, and Cinnamon is recessive to Chocolate. This Oriental Shorthair is sporting a beautiful Cinnamon-colored coat.
Fawn is an even further dilution of the Cinnamon gene. It is most commonly seen in breeds like the Abyssinian or Oriental Shorthairs. These rare and colorful dilutions are more likely to appear in pedigree or purebred cats that have been specifically bred for coloration.
4. Lilac or Lavender
Known as "lilac" or "lavender," this beautiful pastel color isn't actually purple. Like Fawn is to Cinnamon, Lilac is an even lighter dilution of the Chocolate gene. As recessive traits, dilutions like fawn and lilac are rare even in pedigree cats.
Cream is a dilution of the Red gene (commonly called orange/ginger) in cats.
A cat with Smoke coloration will have a light silvery undercoat, ruff, and ear tufts with a black topcoat and points (the face, ears, feet, tail). Smoke can come in longhaired or shorthaired cats.
The chinchilla coloration is most often found in Persian cats, and can actually present in "Silver" or "Gold". Like the Smoke coat, in Chinchilla coats to the cat's undercoat is pure white, while the tip of the hair is black, giving the cat a shimmery, silver appearance.
Edit, 8/13/17: A correction has been made to Cinnamon; it is a dilute of black, not chocolate.