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.
"Fist to five" check students rate their understanding by holding up the appropriate number of fingers. The goal is for everyone to be in the green. Great way for students to self-assess their understanding and help you to gauge student understanding.