There are 4 coat types in Ragdoll cats: Traditional, Mink, Sepia, and Solid. The Ragdoll breed was originally created by Ann Baker in the 1960's by mating a solid black cat with a solid white cat, and then Anne also went on to produce mink and sepia coat types, along with the traditional coat type, in her original Ragdoll lines. Mink, sepia, and solid coat Ragdolls have been around since the creation of the breed, and all of these colors are recognized as pure-bred Ragdolls, and are registered as such under TICA.
Mink vs. Traditional: Mink Ragdolls have a thicker, plusher coat than traditional Ragdolls, often with an extremely plush tail.  The coat of a mink is smoother and much softer than traditional Ragdolls.  Minks have a richer colored, more eye-catching coat than traditional Ragdolls.  Mink Ragdolls are born with their coat color.  Traditional Ragdolls are born completely white and start slowly acquiring their color between 4 to 14 days old.  Minks are pointed (darker ears, face, feet, and tail), but their body color is darker than traditional coats. Minks usually have aqua colored eyes (sea blue green) instead of the blue eyes that the traditional Ragdolls have.  Aqua eyes can vary from blue with just a small hint of green to almost fully green eyes, but the most common is a very even blue green.
Sepia: Sepia Ragdolls are substantially darker coated than their mink Ragdoll siblings.  Sepia Ragdolls have the thickest, plushest, and softest coats of all of the pointed Ragdolls. Sepias are pointed (darker ears, face, feet, and tail), but their body color is darker than traditional and mink coats. Where mink Ragdolls usually only have aqua colored eyes, sepia Ragdolls can have green, gold, blue, aqua blue, or a rainbow of other eye colors. The most common eye color in sepia Ragdolls is aqua or green.
Solid: Solid Ragdolls are the darkest and highest contrast of all the Ragdolls.  Sepia, mink, and traditional Ragdolls are all pointed, and have varying shades of color throughout their coat; i.e., darker ears, nose, feet, and tail.  A solid does not have this variation, so a black and white solid will have the strong bright white contrast against the rich dark black coloring.  Solid Ragdolls have a very soft, thick, plush coat, similar to mink and sepia Ragdolls.  Solid Ragdolls can have green, gold, blue, aqua blue, or a rainbow of other eye colors, but most often have green or gold eyes. 

Traditional, mink, and sepia Ragdolls' color continues to deepen and darken as they mature, until they are up to 3 years old.  Solid Ragdolls are born with full color, and they do not darken or lighten as they mature... their coat color remains the same.

COMMON:  seal and blue
LESS COMMON:  flame, lynx, and tortie
LEAST COMMON:  chocolate, lilac, cream, cinnamon, and fawn

Seal mitted TRADITIONAL kitten

Blue Colorpoint MINK kitten

Chocolate SOLID kitten

Seal Mitted MINK Kitten

Blue mitted MINK kitten

Blue colorpoint SEPIA kitten

Lilac mitted SOLID kitten

Cream Mitted SOLID Lynx Kitten

Black SOLID adolescent