I've only played a one-shot so far, but I enjoy Down Darker Trails, a supplement for Call of Cthulhu 7th edition. I've been a fan of CoC since way back, the system feels very intuitive. The Cthulhu Mythos goes well with everything, too.
I don't have any first-hand experience yet, but I'm excited to try Weird Frontiers. It's a weird Western game that uses the Dungeon Crawl Classics system. All of the books and adventures were available from Bundle of Holding a while back.