I have a metric ton of Christmas stuff too, and I don't consider Christmas a religious holiday. I've argued for a long time that it's a very cultural holiday in the U.S., especially since that vast majority of the things we associate with Christmas have nothing to do with Christianity but rather tradition, commercialism, and Paganism.

I look for cards that are blank inside. Those can be hard to find, too, but it's probably easier than finding NY cards!