Here's a little clip that snaps onto the Prusa rods ). I use it to hold wires against the rods instead of zip tie. It is a bit more polished looking and the wires can be pulled out if needed (and the clip moved or snapped off the rod without tools).

An SCAD file and an STL that prints out two clips is included. You may need to adjust the variables in the SCAD file depending the tolerances of your printer and the bundle of wires you're trying to clip.

Tested for 5/16" rods, but should work for 8mm - if not let me know.