Have you checked youtube for filk? Some is fan music based on popular characters of the spec-fiction world, other is music by writers to complement their own stories that may or may not have been published anywhere. No bets on how much of it will be about fairies (vs other spec-fic beings) or how much is pleasant to your ear, never mind actually good. And unfortunately youtube has a decidedly unsophisticated search facility for separating music from other kinds of filk postings.