In The Wheel of Time, an inhuman race of creatures with human-like body but looks also resembling that of foxes. They also might be related to the Aelfinn.

Like with Aelfinn, nothing about Eelfinn is known about except the part about their dealings with humans (assuming they do have other life than that; they might even be synthetic on-fly generated creatures). People go to Eelfinn to make wishes come true, literally. Eelfinn can make things happen; it is not known what are the limitations of these wishes, but it is good to be kept in mind that unlike Aelfinn, Eelfinn take a price for what they are asked to do. This price likely depends on what is asked to be done, and it can be pretty steep; with the only known example of these dealings, the price was death (well, near-death actually).