Besides the obvious that everything you have that is Christmas is a collection.
I know that some people collect figurines and village sets. I have a small selection of specifically Christmas snow globes that my girls have given me over the last couple of years. My mom was a big angel nut, but not many that are specifically related to Christmas. Now I have quite a big book (mostly children) and movie collection which my hubby says we have to start in November and end in February just to read/watch them all.
