Thanks for sharing Black Acorn. There seems to be an ever-present community of folkies who like the occult.

A good LP which I have is Dark Ships in the Forest.

You may also be interested in Manley Wade Wellman's "Silver John" stories, though they're very solidly in the fiction vein of writing. They do contain a lot of real folk songs and folk beliefs, though they also contain their fair share of fake varieties of both.