A simple V-slot cable clip you snap into the beam.

Designed with inside walls leaning slightly outwards in order to make it much harder to pull them out by pulling on whatever they hold inside.

12 mm wide,
15 mm high, (Change Z-scale in slicer to make it whatever size you want)
Easily printable in Vase mode,
10 clips in a stick, easy to separate by breaking them off

Prusa

I3 MK3S

No

No

0.3

Print in Vase Mode at 0.4-0.5 mm layer width.

The multi clip version has small circular pads at the ends to make sure it sticks to the bed without any skirt/brim.