You want to open a can of awesomeness? Well you got it. This is by no means an exhaustive list nor any that covers the whole spectrum. Some bands are serious others much more lighthearted. Generally all of these have strong folk metal influences drawing inspiration from the middle ages (fall of Rome to fall of Constantinople). Go wild. If I were to do a "top five tracks" from a few bands I would choose Cruachan, Heidevolk, Månegarm and Skálmöld
Cruachan - irish/celtic
Eluveitie - celtic gaul
Feuerschwanz - german "high medieval"
Equilibrium - german
Heidevolk - dutch
Norse/Viking (here I just dump a bunch) - Amon Amath, Brothers of Metal, Ensiferum, Månegarm, Skálmöld, Tyr
Alestorm - PIRATES, a humorous bonus for the funzies
I went to Folsom Street Fair many moons ago, and had the epiphany "I am absolutely not man enough to fuck these dudes." I don't know how the stereo type of manly men only fucking women is supportable. It's like saying "real men drink french vanilla iced coffee slushies", meanwhile the "weak" men are drinking straight up espresso.