thumb prints made into Christmas lights. Easy craft to do with the kids. To enhance this, I might extend the strand each year, so by the time they are older, you have a long string of thumb print lights.
Some Christmas cards are cute enough they deserve to be framed. Remove the oval inserts from wallet-size oval picture frames, and use them as a guide to find parts of Christmas cards that would make nice backgrounds.
Vintage Christmas Bells made from Vintage Christmas Cards. Made these long ago. You cut the cards into the shape you want, poke holes along the edges, then do a simple crochet stitch in the holes. Then crochet all the parts together.