Have you ever used one of these? I've used them to hold sheets of paper together, but I had to look up the actual name, nothing fancy, just called "binder rings". I'm not sure how I came to acquire this one, but it makes a really fantastic large stitch marker! It opens too:
I peeked online at some office supply stores and you can get 8 or so for about two dollars...even better! They make plain metal and rainbow colors too. It doesn't take much to impress me, so glad for my junk drawer today!