Spotted Tabby is not yet standardized by AFRMA
Color is gray with black markings/pattern which consists of a dorsal stripe and spots on the sides and face (most spots run together as adult). Not to be confused with Merle. Other colors possible. The color of the dorsal stripe/spots is the base color, i.e. a Black Spotted Tabby has black stripe/spots and the gene dilutes the body color making a gray background.
Marble is called Spotted Tabby by AFRMA.
It is known for the line down its back and the spotted pattern. It can come in any color and even have markings or different coat types. It looks best on dark colors.
There were some major tooth issues within the variety but many lines have bred it out and have reported no more such issues.
Pics to come....
My Spotted Tabby is a new line to me as of July 2018. I received the start of my lines from Enchanted Hills Rattery in Kansas & Moonshadow Mischief from Pennsylvania.
My lines are Dumbos.
I am working on a Marten-Spotted Tabby line
I will also have a dwarf Spotted Tabby Downunder line