Odin, who has always had a particular resonance for me.
The Green Knight, from Sir Gawain and the Green Knight, who I'm playing in a PBeM. I am planning on going through Tolkien's translation of this. My character is based on a sloppy interpretation from a mythology book I had as a kid. The poem has a lot of details I had missed, like the Green Knight being from a place near "Logres".
Most recently, I've had an idea floating in my head, more of a composite than anything directly from mythology.
A tall man, antlered, with jet black skin, clad in robes, a sword belted at his side. His eyes burn red. Nine queens surround him, dressed all in black, as if in mourning. The Nine Queens can become black swans.
This is, I think, mashed together from Celtic myths (the antlered man is, I believe, Cernunnos or Arawn), Arthurian (I seem to recall nine queens in black escorted Arthur to Avalon. Or maybe it was 3, and the nine is from elsewhere.), and wherever Swan Lake is drawn from (the queens being swans).
I have a sharp image of the king and his nine queens standing in a clearing in a dark forest, the trees leafless and the ground barren and fog-shrouded. It is night, a sliver of moon casts a bluish light on the scene.
The queens stand around the king in a circle, naked swords in their hands, their faces veiled. The king stands with his eyes flashing and his right hand raised, commanding.