Pen Magnet
We always have a block of paper hanging on the fridge, and a long time ago, I made a magnet to fit on a pen, with two small magnet, a rubber band and plenty of hot meld.
Now that I have become a master of TPE printing (not really, I have made three none-catastrophic prints) I have updated the rubberband design.
I made three designs/iterations, all for a 10mm diameter pen. One for a 5x5x5mm magnet, the next for two of those 5mm cube magnets, and the last for ø8mm and 10mm high round magnet.
My product review would be that the one with one cube magnet is nice and small, but just a bit too weak. The one with the cylindric magnet is quite big and a bit too strong. The one with the two cube magnets is just right.