Vikings theme

Vikings:

Vikings follows the adventures of Ragnar Lothbrok the greatest hero of his age. The series tells the sagas of Ragnar's band of Viking brothers and his family, as he rises to become King of the Viking tribes. As well as being a fearless warrior, Ragnar embodies the Norse traditions of devotion to the gods, legend has it that he was a direct descendant of Odin, the god of war and warriors. (source: imdb.com)

The theme is dark and mysterious and fits the series very very well.

Fever Ray - If I had a heart

Spotify playlists for tv-series 3

TV themes soundtracks
If you're looking for a tune from a tv series, current or from way back when..there's a big chance you'll find it here.
TV Themes Soundtracks by Becky Ballantine

Supernatural
The 8th season just started. With lots of classic rock you know or might not know yet. I didn't know Blue Öyster Cult until about 4-5 years back when I heard a song of theirs in Supernatural. Best discovery ever.
There are various people with playlists of Supernatural out there, but this list had the most at the moment of subscribing :)
Supernatural by Kyle Healeas

Community
Not really sure about the music in Community, but then again, if you don't notice music all that much, it's a sign that they're good picks.
Community Soundtrack by Robin Rodgers

Homeland
If you haven't seen season 1 of this, go watch it right now. Check out music that fits the series.
Jazz music inspired by Homeland by Paul Dahill

Mad Men
A great series that I should really start watching again.
Mad men by Paul Dahill