I have a small little black one that is in one of the kits. It has the two long slots for feed dogs, and two small holes each one in front of the slot, but on opposite sides. I hope that makes sense...if not, I can take a pic.
There is also a large plate that has a small little cog in the middle. Does anyone know what that's for? There is also a plastic needle threader. I'm curious how that thing actually works, lol.