By coincidence, a few weeks ago Radio 4 Extra ran a series of readings of weird tales, and among them was Priestley's 'The Grey Ones'. I had always assumed that, while his famous Time Plays flirt with the paranormal/mystical, Priestley was mostly concerned with what might loosely be termed social realism. But it turns out that he ranged rather widely and - in a very prolific and long career - often tackled horror, science fiction, and the supernatural.
My ignorance of Priestley's contribution to genre fiction is a bit embarrassing, as I really should have known that his novel Benighted was the basis for a classic horror movie.
Overall, the Valancourt site is well worth perusing if - like me - you have a mental file of titles you once read and really would to read again.
For instance, there are the novels of John Blackburn. Blackburn is almost forgotten today, but he was a kind of proto-James Herbert (it's hard to believe that Herbert didn't take Blackburn's novels as a template for his own, so striking are the parallels). His books combine the horror, thriller and sci-fi genres, and he was an early exponent of what is now termed body horror.
I read Bury Him Darkly (1958) as a wee lad when I encountered a dog-eared paperback edition in the early Seventies. A strange artefact is unearthed in a family crypt, and it has terrifying powers to alter the minds and bodies of unwary meddlers. There's a quite loopy plot strand dragging in the Holy Grail, which isn't bad for what is in fact an alien invasion story. This is a book in which the idiot who opens the crypt, as is the form in these cases, 'dies a horrible death, raving mad, and whatever he has unleashed is not done killing. Four unlikely allies—a clergyman, an ex-Nazi scientist, a journalist, and a historian—must come together to stop it before it destroys all of humanity.'