Filament Clip. Specifically for 1.75mm dia filament.
There are many available, but I designed this one and have been very happy with it. it has a long channel for the spool edge so it can grip onto even those wonky, uneven edges and remain stable. I print it with 3 walls and so far have not had one break, or really even bend. I have filament from Esun, Sunlu, Elegoo and some Amazon brand; this clip fits on all of those spools.
Filament_Clip.stl | 608.3KB |