One of the claims of some Wiccans (actually, I hope no gets offended by this, but), ESPECIALLY some AMERICAN Wiccans is that Gardner's etiological myth of a pre-Christian Wicca in Great Britain means that it was practiced by the Celts. Honestly, I think these people think that the Celts were the only people in the British Isles, which is something Gardner didn't think, and anyone who has studied a touch of European History should really know better.
So they conflate Wicca (specifically) with things Celtic, which is nonsense. Wicca has pretty much no relationship to Pre-Christian *or* modern Celts.
I really doubt we Wiccans are what you're looking for if you're looking for either celtic things or exclusively magical things. We are a religion, after all.
Edit: Ne Obliviscaris. We Campbells will @#%& you up. :) I never had more fun than going to Scotland with a big-giant bunch of Campbells, to visit another big bunch of Campbells...and there was only one fight, and it was between brothers.I took this "Anthropology of War" class, and the guy teaching it (who started the field) asked who the most vicious fighters through history were to this day. People said various terrorists, Zulus, Native American Tribes. I said "Well, most of my immediate ancestors are Scots-" and he goes "that would be them!"