I'm looking for manga where there is the concept of faeries in it. The British mythological types like changelings, brownies, Oberon, Titania, and the like. Examples include Hakushaku to Yousei and the Ancient Magus Bride. Thanks!

Uh... These fairies only vaguely draw from mythological fairies:
Fairy Cube
Ginzatoushi to Kuro no Yousei - Sugar Apple Fairytale
Kirikagohime to Mahoutsukai
Mein Ritter - Watashi no Kishi
Shounen Hakaryuudo

You can always take a look at the Fairies or Celtic Myth tags. Do you have any other specifics, demo/genre/etc. wise? Or plot wise?

The only one I can think off the top of my head right now is: Crystal Dragon which is ongoing.

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Western Webcomics

Yousei Ou, though unfortunately it's not scanlated.