I think Nirvana breeds are all there own creations, hopefully they will not name a strain ThunderFuck, lol.

Lots of other good breeders out there too, DNA, Dina, Ethos. Barneys, the list goes on. Delicious Seeds is a great breeder but their packaging sucks so I dont buy from them anymore. 

Nirvana is a reliable go to for me and they have excellent customer service, The main thing I like about Nirvana is when I get a pack of 5 seeds I don't get a huge variety of phenotypes, That tells me they know how to and take the time to stabilize their strains.