Oh Holy Night - 1960s recordings have more orchestration and will likely have all verses.
Look for compilations of Boar's Head festival songs for a medieval flavor.
Older Mormon Tabernacle Choir recordings are almost always religious/non-secular.
Handel's Messiah - initially associated with Easter, but now more so Christmas. Its glorious, long and should be played with the volume set to 11.
Patapan - great instrumental for background music at gatherings. Also look for additional "brass choir" classics.
Good King Wenceslas perhaps
While I’m not a Catholic, John Michael Talbot’s The Birth of Jesus is a great Christmas album. I usually add in his “Advent Suite” while listening to it.
This old record set is pretty good, got some of the dumb songs on there, but I'll admit I mostly play record 5.
I use Pandora for work music. I know what you mean about trying to find "good" stuff, because most modern christmas music is soulless garbage.
The station I settled on is a country christmas station. it encompasses the oldies like Sinatra, Elvis, etc., as well as newer songs from country artists, who actually give the source material the respect and love it deserves.
Just me two cents.
I usually play several Southern Raised (youtube.com) songs.
Peter Hollens has some great stuff, Lindsey Stirling too