I have often seen designs of little hooks or clips to hold filament onto a spool. I thought I would take a shot at my own design for my Prusa i3 MK3. It holds any 1.75mm filament (may require sanding, but mine worked first try) and fits the metal frame.
AIO Robotics PLA
Because the hole is important, you may need to drill out or file out the hole. I had no issues but it is better safe than sorry!