I replicated the Buffalo Sabres 3D-style helmet decals from the Winter Classic, and I have a few extras. They were unfortunately quite expensive to make, because of the 3D effect, so I'm asking $40 for a pair of decals. They are a flexible rubbery material with adhesive backing.
I also have a limited selection of the number decals, which are $10 for one number (2 digits) or $17 for two numbers (4 digits).