Oh I didn't think to look at a Joannes fabrics for a Boppy/pillow. I'll check it out. Thanks!
They can be used on any crescent shaped pillow. Just not the new version they have come up with. I got my " boppy" cheap at Joanne fabrics. It's not boppy brand, but I use the covers.
I don't think they are universal, unfortunately. I'm pretty sure each brand has their own stuff.