I tried the pedicure toe separators for my bobbins and like them just fine.
The marking pens that come with the different colored chalk that's about 1/8" thick. They're red and Hancocks had them out a couple of years ago. GARBAGE!!! They're so hard they move the fabric, so soft they break easily. Tried the one that looks like an automatic pencil and I like it much better. The "press down in the center and twirl this around" circle cutters are a waste too.