I believe it was Mark Gatiss who came up with the folk horror label and named those three films. We were talking about this on another thread. I honestly don't see Witchfinder General as folk horror. It's a film with lots of countryside but its not something in the countryside or the folk residing there that's the horror, it's plainly the witchfinder and his henchmen who are the badies. But then I'm not entirely sure what folk horror is exactly.
I really like four of Ben Wheatley's films - Kill List, Siteseers, A Field in England and Free Fire. I think there is something very special about Field in England though - the ambiance of it, and the characters - although I suppose it teeters on the pretenscious, I really, really enjoy it. I tend to really like the soundtracks to his films, they're definitely on my wavelength.