Folk metal is odd in a great way; some of it is overtly folkish like Korpiklaani with their instruments, or Skyclad with their usual rhythms (and often their instruments as well); then there's bands like Ensiferum and Falconer that lean further into the metal side, though the folk elements are still clear.
Then there's pirate metal, my favorite sub-sub-genre. Alestorm, for example, got me into music BIG TIME.
Frankly, Folk Metal, while not my favorite subgenre anymore, is still one of my top 5.