A Virtual Sticker Wall!
Add a page to the Sticker Mule website called https://www.stickermule.com/wall and make a virtual wall of stickers that randomly selects and shows stickers that people have made with sticker mule. Each time someone orders stickers you can add a little "Add to sticker wall" button to opt in to have your design be included on the virtual sticker wall. I think it would be a great way to show off the diversity of stickers made by sticker mule, the cool art and capability of the stickers. But mostly, I think it would just be fun.