For your fairy themes in folk tales....here are a few suggestions:

a) Irish Folk and Fairy Tales Omnibus by Michael Scott ( huge and comprehensive.)

b) English Fairy Tales   by Wordsworth Classics ( 40 of the best known.)

c) Mythology of The British Isles by Geoffrey Ashe ( painstakingly researched, retelling tales from the year dot to the 9th century AD and an extensive bibliography.)

d) Edmund Dulac's Fairy Book ( draws upon the folklore of Russia, France, Italy, England, Ireland, Belguim, Serbia and Japan.)

e) Elves, Trolls and Elemental Beings: Icelandic Folklore translated by Alan Boucher.

f) Russian Folktales by W.R.S.Ralston (unsure if still in print?).

Poetry wise, Yeats as mentioned above is rich....The Hosting of The Sidhe springs to mind, as does The Fairies by William Allingham.

Best of luck, sounds a lovely project.