Folk metal isn't super popular but its by far my favorite genre. Bands from all over the world incorporate their traditional music leading to some really cool shit.
Edit: Posted the wrong link, this is a much better example (https://www.youtube.com/watch?v=iijKLHCQw5o)
Eluveitie is great, I did just give Leaves' Eyes a try due to your incorrect link and it feels like the kid Nightwish and Epica are fighting for custody over
Lol I like that