Right now they have these magnets at the Target Dollar Spot. They also have superheroes. The sheet that you punch them out of is the perfect thickness to save and make a magnetic puzzle. Punch out the magnets and leave the outline on the fridge or magnetic board for your child to put the pieces back in.
You can also do the same thing with stickers. Peel the background off of a sheet of stickers (leaving the stickers behind) and putting it on a piece of paper. Have your child match the stickers back into the outline.