We keep a magnetic notepad on the side of our fridge for our grocery list. We had a pencil cup on the counter to have pens and pencils handy but it was slightly annoying and often in the way. 

I recently purchased a mixed package of larger magnets and the recent remix of my model by @matthewstewa_1631953 inspired me to change from a fixed model in the original to a customizable model. Parameters in the included Fusion 360 file allow changes to the height, depth, width, thickness of the back wall as well as the diameter and thickness of the magnets. You can also edit the rectangular pattern to change the number and distribution of magnets. In addition to the one on the fridge I also have a larger one attached to the door of our breaker box in the garage to keep a few small tools handy.

This model is designed for the magnets to be glued into the recesses on the back. A tiny drop of super glue is all that is needed. I tried using snap-fit but could not get it tight enough to prevent them from popping out. 

The STL file is based on 10mm x 2mm magnets. But note, at least the ones I have, are more like 1.8mm thick. The filament is Polymaker PLA and it took about 1 hour 15 minutes to print on my MK4 with input shaping.