I can recommend breeders for those who live in Europe (Or should there be a seperate thread for it?). I only recommend someone that I already bought a snake from. They don't have a website, since I don't know if I can add more information about them for now I only add there names:
Steven Bol (THE best breeder in the Netherlands for garter's in my opinion)
Sabine & Gijs ( they are on the forum here
and their collection is still growing, but I can certainly recommend them )