Nice find! I need to see if i can find my copy of "The encyclopedia of faeries" it's old as dirt but its super informative on old folklore and includes excerpts, stories and tips on how to get your baby back when changelings take it.
One of my fave authors, Neil Gaiman actually uses old folklore in alot of his works and his writing is just plain awesome. Currently re-re-re-reading "Good Omens" right now.
Terry Pratchett is pretty righteous while I'm thinking about it.
For me personally, it doesn't even have to be folklore/fiction. I'll just buy old books and read them. Also, as sad as it is to see a library close, those are the best places to find dusty treasures.