I prefer strong flavors too. I've tried probably 40 vendors and these are the ones I have or would re-order from and what I like best from there.
Good Life - Deadly Sin, Spook Sauce, Pink Cupcake
Bryces - ALL of them (they are all vanillas)
Nicoticket - Betelguese
Highbrow - Crème Brulee, Caramel Cake (extra flavor from here)
Velvet Cloud - Mewlews Magic, Vanilla Custard, Straw Gwab
Vapelicious - Seattle Gooey Butter Cake, AGs Dream
Vapor Chef - Butter Beer, Pina Guavada
Vapor Room - Buttery Popcorn, Horchata