m0useanswered grow question 3 years ago https://www.cannabis-seeds-bank.co.uk/
attitude seed bank, ships to USA, has almost every breeder out there.
Legit, used them before.
I've read bad things about crop king, would not recommend. but might be my own personal Bias.
As for a breeder that makes a outstanding Green Crack I have zero experience, never grew it, But off the tip of my head, Humboldt Seed Organisation.
Best to google and see what the community is saying.