It would seem to me that folktales and fairy tales would be in the public domain, except of course for modern and contemporary authors who adapted them in their original works, such as Angela Carter and Donald Barthelme. I'm wondering if the copyrights have run out on Andrew Lang. His collections as well as those of the Grimm Brothers would be a nice addition to the LitNet.

Speaking of the Grimms, some philology and linguistic texts would also be worthwhile. So would The History of the English Language by Albert C. Baugh.