Learning about Celtic Mythology can be a minefield. These are some articles that I have compiled from research that provide the bare bones of these ancient stories, along with some background articles. They are a great starting point for those interested in being a Bard. If you want to learn more, suggested reading is given at the bottom of the page.
Irish Mythology
#1 Primary Sources of Celtic Mythology
#2 Tuatha Dé Danann (Children of Danu)
#3 Inisfail, the Island of Destiny
#12 Tír na nÓg – Land of the Young
#15 Áenach Tailteann and Lughnasadh
Welsh Mythology
#16 Sources of Welsh Mythology
Scottish Mythology
#28 Hebridean Mythology and Folklore
Cornish Mythology
Breton Mythology
Further Suggested Reading
Lady Gregory’s Complete Irish Mythology
The Táin: Translated from the Old Irish Epic Táin Bó Cúailnge
The Lore of Scotland: A guide to Scottish legends
LEGENDS & ROMANCES of BRITTANY – 162 Breton Myths and Legends