osdon

It mostly depends on how broad you want to take the Celtic heiritage. For some it's as basic as being from Irish/Scottish/Welsh descent, and to some it is limited to going back to specific cultural things like the year feasts (Samhain, Imbolc, Beltain and Lughnasadd) or Hurling (of which a form is attested in Irish stories that go back to at least 800 A.D.). Personally I don't know about the magical aspect related to Wicca, but the philosophy of "when it harms none, do as you will" is a good one.