Probably every big reseller with the known breeders
which you already find on this site.
You can look here at the Breeder pages, which reg strains they got
(maybe not all strains are available anymore)
SensiSeeds got more than 40 regular strains listed
Humboldt Seed Company got more than 10 listed
Super Sativa Seed Club got also more than 10 listed
there you will find probably some good genetics