Cricut Pen holder for Sharpie. Extra fine has been tested, Fine is still under development.
It should be adaptable for most pens. Check out the spreadsheet in the Freecad source.
Print .2mm layer height, no supports. Flip it so that the small hole side is down.
A brim can be handy to make sure it doesn't fall over, but I've also printed it successfully without. It would probably be better (more flexible) in PETG, but works fine in PLA
The author marked this model as their own original creation.