YALL. Holly Black has a list of resources she's used for writing her books on the fair folk. I'm OBSESSED. I love her work and world building. it's so true to the heart of faeries
Some other resources that might be worth checking out (not strictly about faeries but related):
The Corpus of Electronic Texts, or CELT, a collection of Irish cultural materials. This includes English translations of Irish myths.
Mary Jones - similar to CELT, and a resource we used for translations in the Irish mythology class I took in undergrad.
An Encyclopedia of Fairies by Katherine Mary Briggs, a British folklorist.
The Folklore of Cornwall by Ronald M. James. Unfortunately this book is harder to access and is often only in university libraries, but if you're interested in piskies it's a potentially very helpful read.
Traditions and Hearthside Stories of West Cornwall by William Bottrell.
