Reddit reviews The Little Book of the Hidden People: Twenty stories of elves from Icelandic folklore

You'll have to forgive my loose understanding of the mythology of that region of the world - but would Icelandic Folklore fit into those themes as well?

There's a pretty good book (among many others I'm sure, there was another I tried to find that had more than just elves that I read awhile back but I can't seem to find it) that has a lot of short stories and introductions to the various types of folklore and legends of Icelandic mythology, which I think is in some way related to other mythologies of the Scandinavian region? Which should include celtic/irish/norse mythology as well?

I might be wrong (I'm a greek/roman myth guy, myself) but perhaps that book will give you good ideas anyways. "Hidden Folk" are a very popular Icelandic myth, in particular, hence the name of the book.