By album, from my own Skyrim playlist, in Brutal Legend format!
Viking/Folk Metal
Bathory - Hammerheart, Twilight of the Gods, Blood on Ice
Wolfchant - Bloody Tales of Disgraced Lands, A Pagan Storm, Call of the Black Winds
Ensiferum - Ensiferum, Iron, Victory Songs, From Afar
Demonaz (of Immortal) - March of the Norse
Falconer - Chapters from a Vale Forlorn, The Sceptre of Deception
Speed/Power Metal
Stormwarrior - Stormwarrior, Heading Northe, Northern Rage, Heathen Warrior
HammerFall - Glory to the Brave
Epic Heavy Metal/Epic Doom
DoomSword - DoomSword, Resound the Horn, Let Battle Commence
Rebellion - Sagas of Iceland - The History of the Vikings - Volume I, Miklagard - The History of the Vikings - Volume II, Arise: From Ginnungagap to Ragnarök - The History of the Vikings Volume III
Amon Amarth is missing from the list, but all of it had a viking/epic battle theme bar for Falconer...which I just wanted to listen to.