Dunamis: From McKiernan's The Eye of the Hunter, the sword of the elfess Riatha, which had the property of drawing power from the lifeforce of ones' friends, prematurely aging/killing them. Great weapon.

Krystallopyr: Giant crystal sword stolen by Taro Ofuchi in The Gamer's Alliance, later used by Kagetsu to <s>defeat Arawn</s> destroy the world

The Krill: Used by Loric Vilesilencer to...um...silence Viles. And the Demondim, although now that I have a better idea about what the Demondim are, I don't see how the Krill would have been of any use.

Mithrandir: A big effing sword.