Hussie has stated that in canon, there are 11 troll blood colors. All the canon trolls not including Karkat (who is a mutant) and Feferi (who's blood is higher than everyone else's), and with the addition of the lime bloods.

Remember though, even while still not canon, different shades are OK, I mean, in my opinion they are.

Because they are just the same color, but with a twist.

It’s like people, OUR skin isn’t all exactly alike.
So why should their blood be?
-Mod F