Recently, almost as a whim, we bought a couple of rectangular drawer organizers. These have become some of my favorite "supporting characters" in my classroom.
These are perfect for holding odds and ends in for an activity. Here are a few ways we've used them--
Hold foam stamps
Hold shapes (or markers or letters) at the easel
[[We were so busy this week that I didn't get a photo of this one.]]
We love that the rectangles fit so well on our easel's tray. That's why we bought them...but we have discovered so many other uses. And these have a rubber padding in the bottom, so there is little noise when you drop things into them.
I may need to head back to Target and get a few more!