Morphs and color phases

How many morphs or color phases are there for Uro's? Come to think of it, are they actual morphs, or just phases?

Actually they are different species except for the geyri. Geyri come in 3 different colors (yellow, red and orange).

Do you mean species, or subspecies? Can a Mali and a Geyri produce viable offspring?

The genus is uromastyx. There are approximately 16 species and some subspecies as follows:
U. acanthinura acanthinura
U. acanthinura nigriventris
U. dispar dispar (rare in US)
U. dispar maliensis
U. dispar flavifasciata (rare in US)
U. geryi
U. alfredschmidti (non in US)
U. aegyptia aegyptia
U. aegyptia microlepis
U. leptieni (non in US)
U. occidentalis (not known in captivity)
U. asmussi (non in US)
U. hardwickii
U. loricata (non in US)
U. ornata ornata
U. ornata phylibyi (not known in captivity)
U. ocellata
U. macfadyeni
U. benti (rainbow or mountain)
U. benti (lowland or orange)
U. princeps (not known in captivity)
U. thomasi (non in US)<---- would give my eye teeth to have a pair of these.

While most of these species are limited by color, some do have variations. Geryi come in 3 different colors; red, orange and yellow. Acanthinura comes in different colors as well; red, orange, yellow and green as well as a mixture.
Husbandry issues have plagued uromastyx breeders for the last 2 decades. We are just now beginning to see limited success with breeding of single species, few have tried interspecies breeding. While I am sure it can be done with the more closely related species, I myself wouldn't try.