My kind of genre.

Here are two more obscurities:

(1) "Shoot that Turkey Buzzard" by J. E. Mainer. Absolutely manic, all-stops-out bluegrass. https://youtu.be/9J1f8Xi3d7Q

(2) The most frightening song I know of, in two versions, "Death Came Creeping into My Room".

Country blues (i.e. Delta blues), Mississippi Fred McDowell https://youtu.be/zhDkA3UvruE

The bluegrass version from Curly Ray Cline. Hard to say which one is bleaker. https://youtu.be/grYy_CW39GI