I'm the founder and artistic lead on the products and UI/UX for Spotted, a not-yet-released app that uses QR codes to protect privacy and help return lost items to their owners.
A few of the Spotted sticker designs — scan the code to help return a lost item.

Step 1: Put Spotted sticker on valuable item.

Step 2: Lose valuable item :(

Step 3: Someone finds your item and scans your code.

Step 4: With the help of Spotted, you are now reunited with your lost item!