Because you can only watch It's a Wonderful Life and Miracle on 34th Street so many times.
In chronological order. Note that for brevity and clarity, this list excludes any sequels to films already featured, and mostly ignores cult favorites that - while bizarre - are still basically trite, family-oriented Christmas fare (e.g., Santa Claus Conquers the Martians, René Cardona's Santa Claus, Santa Claus and the Ice Cream Bunny). Also, some of the films listed may not take place entirely during the holiday season, but instead open around Christmastime or build to a Christmas ending. (A few of them double as New Year's Eve movies, too.)
Documentaries excluded because they have no Letterboxd pages as of yet: Christmas With Dad, The Worst Christmas Jobs in History, Wood of Value, The Truth About Christmas Carols.