I've made a very easy card, inspired by something I saw on Pinterest. I die cut a pine branch (the die is quite an old one and I can't remember the branch) from a snippet of green card and cut the houses by using the bauble die that was the covermount on last Christmas's issue of Die Cutting Essentials and a snippet of red card - I just taped a small piece over the area with the buildings on rather than cutting the whole thing. Then I cut each building away from the rest of the die cut, assembled everything on a card stamped with a Studio G sentiment and hand-drew the strings for the house-baubles to hang from the branch by.
This idea could be adapted to all kinds of other "decorations" - I've seen a very similar thing done with buttons. Snowflakes - perhaps that snowflake confetti that we all hoarded about 15 years ago - large gems or candy canes would work too. It would only take a few minutes to create a set of "same but different" cards, in fact I think I'll go and do that right now!