Pen holder magnet

This little clip has a 3 mm thick x 8 mm diameter magnet imbedded in it.  In your slicer, just add a pause before the cavity in the base is closed up so you can drop in a magnet.  Use a neodymium magnet to maxmize holing power. The clip is flexible so it will hold pens and pencils of different diameters.  It can also hold shopping lists or artwork to your fridge at the same time.  It is simple and fast to print, mine only took 6 minutes with a 0.6 mm nozzle on my Prusa MK3S+.