My teacher uses a Noise Meter similar to this one. The Noise Meter is a cool way to remind students the correct noise level that they should be using! You just use the paper clip and move it to the appropriate noise level the students should be using.
I like this behavior chart. It has each student's name in a slot with 4 cards per slot. The key to what the different colors is at the bottom. I like how this lets a child look to see where they are at any time during the day.