Artifice: Ulm pretender. Essentially a Virtue with Earth and Astral.
Forge Lord: Ulm pretender. A Vulcan/Hephaestus character with Earth and Fire. Forge bonus (naturally), probably fire immune as well. Any number of other cool potential abilties - see the Wikipedia
article.
Iron Council: Ulm pretender. High Earth magic, immobile. An ancient machine created for some unknown purpose. Generates mechanical men when its dominion is strong. Drain immune.
Raven King: Luxury rainbow mage for Man and Vanheim. Has air-1 and nature-1, and glamour. Can also turn into a raven for rapid travel.
Great Wolf: Jotunheim pretender. It's Fenrisulfr, from Norse mythology. Size 6, has a nasty bite. Water and death magic?
Trickster: Another Jotunheim pretender - Loki this time. A versatile giant wizard, with glamour (since he can change shape). Maybe assassination as well.
White Guardian: Vanheim pretender. Has air and earth magic, a magic horn and an absolutely ludicrous patrol bonus (100+). Based on Heimdall, one of the Aesir.