One day - when there are children. each put their thumb print on and add a little feature to say who is who (e. eyelashes for mum, bow for daughter, etc).(Diy Crafts For Christmas)
These torn paper tree cards. You could use photocopied pages of a Christmas story or Christmas carol sheet music.
Thumb Print Reindeer - I love the idea of using fingerprints. Could work for Santa, Snowmen. all sorts! Would make a lovely personal touch to a card.