This is an occasionally updated list of some of the places I find my information: online libraries or compilations of folk texts, important ideas and terminology, and so on.
Online Collections of Folk and Fairy Tales and More
Fairy Tales from Hans Christian Andersen (archive.org)
Folktexts: A library of folktales, folk lore, fairy tales, and mythology – D.L. Ashliman’s online collection of tales and lore, grouped by theme.
Hyakumonogatari Kaidankai – Translated ghost and folk tales from Japan, with descriptions of various youkai and historical/cultural context.
Internet Archive – searchable database of full texts, including collections of and scholarly works on folklore and fairy tales.
Internet Sacred Text Archive – scanned texts of folk tales, fairy tales, tradition, mythologies, and religions from around the world.
Lang’s Fairy Books – The full collection of Andrew Lang’s fairy books, at sacred-texts.com
The Medieval Bestiary – An online collection of creatures from medieval bestiaries, with illustrations and descriptions.
SurLaLune Fairy Tales – 49 annotated fairy tales, including their histories, variants, and modern interpretations; over 1,500 illustrations; more than 40 full-text books comprising more than 1,600 tales from around the world.
Wikipedia: List of fairy tales – Just as the title states.
Folk Song Databases
(I dug these out of my bookmarks from who-knows-how-long ago, and they look the part — but they’re valuable resources nonetheless.)
Anderer Länder Folksongs of Various Countries – A large collection of folk song lyrics, and a few other resources like folk songs in German and hymns.
Folk Music of England, Scotland, Ireland, Wales, & America – Lyrics grouped by country, date, author, and so on, with commentary/history for each song.
The Max Hunter Folk Song Collection – Almost 1,600 Ozark Mountain folk songs, recorded between 1956 and 1976.
Roud Folk Song Index – A Folk Song Index and Broadside Index using the Roud classification system, that “seeks to provide details of English-language traditional songs which have been recorded in any medium.”
Scottish Music Lyrics – A blog of lyrics to Scottish traditional songs.
Traditional, Folk and Old Song Lyrics Collection – More than 3,700 song lyrics.
Folklore, Fairy Tale, and Tradition Commentary/Research
SurLaLune Illustration Gallery – over 1,500 fairy tale illustrations.
My Pinterest board of fairy tale illustrations – over 700 vintage and contemporary illustrations/artworks of or inspired by fairy tales, folklore, and mythology.