Good breaders in my view: Mr Nice seeds, Bodhi seeds, DJ Short Seeds, dark horse genetics, Sin City seeds, seed junky seeds, karma seeds,Aficionado, symbiotic, haute genetique, Humbolt Seeds
Some strains I can recommend with high yield and high THC: Super Silver Haze, Dream Lotus, Wedding cake, Gelato variations, bruce banner #3, chocolope, master kush, Sunshine daydream, many Gorilla Glue #4 crosses, Pineapple Skunk, Headband, Headbanger, blueberry to name some. If you can't find the strain or its not available, you can go to seedfinder and learn about the linage of the strains. You can then look for a good cross with another high yield/high THC strain.
This is for indoor growing and only my preferences. Good Luck!