I don't know if you have searched in the Digital Tradition database first, but you are sure to find the remainder on one of the following sites.

http://www.osmond.com/chill/christmas/carols.htm

http://www.geocities.com/Athens/3680/xmasindx.htm

The first site also includes some contemporary and a number of traditional songs where Christmas is mentioned, though not the main theme.

Seasonal greetings,

Colm