There are some other ER11 collet holders here on Thingiverse but I wanted labelled and compact so I wrote this one (openscad)

It's for the collet set I got here:
https://www.aliexpress.com/item/1243885567.html

The letters print out sideways for best definition but if you wanted them coloured then you could rotate them to the top and pause just before the letters are printed to change to a different colour filament.