Beads! I have found that even my students who are totally blind and have severe cognitive impairments, can string beads. It's one of the few assignments that almost everyone can do independently. I have a giant bin full of tiny plastic beads waiting to be strung on thin wire or pipe cleaners.
But I asked the students, who are ready for more aesthetic ownership, to make their own beads. This also worked for the students who completed their clay assignment early and had a couple days to do a project on their own.
The processes was very simple. They rolled little balls of clay and poked a thick gaged wire through each one. The clay (and the holes in the clay) shrink with drying, so some of the beads had closed up and were useless. If there is just a tiny piece of clay blocking the hole, a heavy wire and a little work can open the hole again, but it's best to just be sure they are big and straight enough when they are first made.
After firing, the beads were colored with Sharpies or painted before being strung on thin. Many of the beads were fairly large so the results were heavy, Wilma Flintstone style necklaces, but my students didn't mind. They were so pleased with the results, I may need to come up with a paper bead lesson for them.