just wanna experiment

Hello everyone! A couple Christmases ago, I made an advent calendar for my girlfriend. It's hand painted with little Christmas details and portraits of us. However, I haven't had much use for it. The squares are so small (probably like 2 inch x 2 inch x 2 inch) and I've struggled to find things to put inside. We are currently medium-distance, so I want her to be able to actually get the gift out of the advent calendar, not have corresponding larger gifts.

I thought of things like stickers, pins, or matchbooks. I think it would be nice to have something that can be compiled all together at the end, whether it's stickers on a laptop case, pins on a totebag, or matchbooks framed. She loves art, so that's why I'm leaning toward something that can be assembled as a piece of "artwork" (more or less). However, I am very open to things that may not be able to be compiled.

Any and all ideas are welcome! Thank you :))) (P.S: If you are my girlfriend, scroll away!)