I was listening to Holiday Cd's on CD Baby and although there is a Holiday genre - for all styles of music, you can also type in Folk - Holiday for a lot of folk or celtic holiday CDs.

I listened to a few and came across some artists (unknown to me) who had some nice Christmas CD's.

One is a singer named CARRIE BOWEN who has a CD called,
"Sleepy Little Town." You can only hear short samples of each song but heard some songs on this CD that sounded very nice.
Especially liked, "Mary's Lullaby"   "Noel" and "More" from this CD.

Another nice Christmas CD is by another unknown folk singer named,
LEAH SALOMAA. She has a CD called, Under a Winter Star." Really liked her version of "All Through the Night."

A well known Celtic type folk group who I have known about for years, called GOLDEN BOUGH, have a very nice CD called, "Christmas in a Celtic Land." I have seen this group in concert over the years and they sometimes tour in Europe and all over USA. Originally from California but now they live in Oregon and have been together for many years. Really like their Christmas CD.