I designed this spool holder from scratch because I had different spools that had different center hole sizes and offsets. In particular the FlashForge Creator Pro has 2 spools, and the spool on the right side requires the spool to be mounted backwards from the left side.
Using the spool holders that came with the printer resulted in the thread not going cleanly into the feeder, and caused it to get tangled around the spool.

I used OpenScad to make it customizable.