Chance
A god mentioned in The Colour of Magic and described as female, having just lost her last pawn in the gods game "by having just run her hero into a house full of gnolls". Her hero did not survive, and Chance was forced to withdraw from the game.
Whether she is the god of Chance or the anthropomorphic personification of Chance is unknown. She is the one god that does not favour million-to-one chances and she has 999,999 casting votes in the matter.