Hi

I'm trying to find a drama that have folklore in them. I've seen the tale of the nine tailed, scholar who walks the night, mystic pop up bar, Korean odyssey, goblin and currently watching my roommate is a gumiho. I really like mystery, folklore and historical dramas. If you know any good drama please recommend me:)

Arang and the Magistrate - it is chock full of fantasy elements and also a very good drama!

Legend of the Blue Sea - mermaid, modern

My Girlfriend is a Gumiho - modern 

definitely Gu Family Book

Along with the Gods: The Two Worlds and sequels. It is movie (not drama), but very well done. It has some afterlife mythology.

And there are several series based on Hua Mulan if you search for Mulan on mydramalist. I would also highly recommend the American series The 10th Kingdom if you haven't seen it. It involves a parallel world populated by fairy tale characters.