I love making what I used to cavalierly call doodads. However, in the interest of sounding like a professional artiste, I now refer to them as inclusions. Yesterday, I made quite a few of these out of black air-dry clay. They may be hard to view properly, but once I have painted them, and added a little metallic sparkle, they will be quite presentable. Look for them in future mixed media art quilts.
I also produced a number of stamps, this time out of Styrofoam. Styrofoam, I find, takes paint and gesso very well. It’s also super simple and fast to cut out and glue together.
I use an exacto knife to cut my shapes, and rubber cement to bond those shapes to a base. I typically have 3 layers, although 2 would probably be adequate, and make myself a small cutout for my fingers on the back layer (see shape below). You can also just glue a small rectangle on the back for your fingers to grab. Why 3 layers? It seems to give the stamp weight, substantiality. One layer feels too light, and is more easily damaged. The finger grabbers, of course, prevent those oh-so-gauche fingerprints from surrounding each and every design on your fabric or paper.
I do both negative and positive shapes, and add any details with a ballpoint pen. It always amazes me how those details show when I brush paint, ink, or gesso onto the stamp and transfer the image onto cloth or paper. The stamps also last a surprisingly long time. I have had some of my styrofoam stamps for at least 7 years now!