FreeCameo 4 Pen Adapter
Printables
7 model
Free
FreeParametric Pen Adapter for Universal Mount (MPCNC)
Thingiverse
FreeEgg Painter Mini Sharpie Pen Adapter
Thingiverse
FreeEnder 3v2 pen plotter plate adapter
Thingiverse
FreeMonster Truck (Holder) Micro SD/Pen/Thumb Tack/Micro SD Adapter
Thingiverse
FreeZero slop/play magnetic CNC/3D printer pen plotter/adapter/holder V4
Thingiverse
Freeikea skadis shelf, hook, pen cup and adapter
Printables