Welcome to the forum Jeremy!
I can't recommend a specific breeder, but if you do a search here for "collared lizard", you will get a list of topics that are mostly "For Sale" ads. You can scan the ads, note who has what, and then research any seller having your desired variety right here in the BOI forum.
"collared lizard" search:
https://www.faunaclassifieds.com/for...archid=5206481
Collared lizards tend to vary in color by localities, with some areas producing very bright blues, other areas producing more subdued colors, but nice patterns. If you can zero in on your desired locality/color, that too will help refine your search for a breeder.
Good luck!