Officially, you get only two color options with the Moto G5 family i.e. Lunar Gray or Fine Gold. But, it seems that there's a Limited Edition "Really Blue" Moto G5 out there!
Shared by Roland Quandt, here is the Moto G5 in "Sapphire Blue" color:
According to Roland, this is the pre-production unit. We have no information when and if it will come out or not!
Would you buy the "Really Blue" Limited Edition Moto G5, if it ever comes?