As a pretty eclectic listener that doesn't didn't usually listen to much extreme metal, Windhand was my gateway drug to stoner/doom; try Forest Clouds and Grey Garden

I also really enjoy YOB (Adrift in the Ocean), Firebreather (Kiss of your Blade), and Khemmis (Hunted), and Monolord has some really fun, almost hypnotic groovy riffs (Empress Rising)