I already know what I'll be using some of them for: holding the leftover bits of custom-mixed paints and plasters that I use. It takes so little for mini projects, I hate to mix up large amounts of custom colors and textures. They tend to dry out quickly in larger containers, so storage has always been a problem. These will be perfect! I'm also going to use them to hold different colors of flocking material, which currently stay in the plastic baggies in which they arrive. I have to pour out piles onto paper plates or into larger containers when I actually use it (and then try to pour the leftover back into the baggies.) This will be a much easier solution.
I think they'll also be handy for storing miniature works in progress, to keep the pieces together and clean. And I can stack them right on the work table within easy reach instead of away in a drawer where they might be forgotten. Maybe it will help me cut down on the UFOs around here!