What area? Which faire? This is (of course) a bone of contention at many places - because while a lot of the musicians would *like* to do more period songs - it's the celtic/celtoid and victorian parlour songs types that are much more popular with the audiences.

Cantaria is a good resource, especially if you, like me, learn by "ear" rather then sheet music. -

this site has a number of links.

The Royal Chessmen (whose site is currently down - at least that's what my browser says) has an archive of popular faire songs. Mintrels of Mayhem, Molly and the Tinker, The Corsiars, The Jolly Rogers, The Pyrate Royale, Wine Women and Song, Jim Hancock, Three Hams on Rye, Women of Whimsey, Tudor Tarts, etc, etc all have websites and most list the songs they do - which should give you a pretty good selection.