Parametric tin can topper
I give my dog a third of a can of wet food with each meal, which means I always have a partially used can sitting in the fridge. Tired of putting foil over the cans, and only finding soda/beer can sized toppers on thingiverse, I made a resizable snap on can top.
This was printed on a Replicator in ABS. It fits a little loosely, but it snaps into place and doesn't come off without a decent amount of force. This should work with all your standard sized cans, soup, tuna, uranium ore, whatever.