Until recently, I had no idea there were such things as Christmas themed postcards. They aren't easy to find in the UK but other countries have an abundance of them. They come in many different themes, but probably the most common are:
Santa Claus/Father Christmas/Père Noel/all sorts of names
and snowmen/bonhomme de neige:
I don't know why, but I find the snowman at the centre above vaguely creepy.