I thought that a visualiser that looks like a spool of filament would be cool. I've printed this one in PLA, with the spool in black and the filament in yellow for contrast.
It attaches via a neodymium 3mmx6mm cylindrical magnet. You might need a tiny drop of glue to join the parts. The magnet should fit tightly - if not, a drop of glue.
I printed this with 0.15mm layer PLA presets, except for the layer height for the filament, which I changed to 0.3mm to give the effect of a roll of filament.
The author hasn't provided the model origin yet.