Signing a.k.a. sign language can be helpful for people who are hard of hearing, as well as for video calls, loud rooms, etc. Some teams like use signing in all meetings because signing is fast, easy, clear, and keeps things on track.
For votes: thumb up means yes; thumb down means no; thumb sideways means maybe. Everyone votes. The moderator tallies.
For clarification: anyone at any time can ask for clarification, by making the one-hand sign "C". Everyone pauses. The speaker takes charge. The speaker and the asker discuss.
For time out: anyone at any time can ask for a time out, by making the two-hand sign "T". Everyone stops. The moderator takes charge. The moderator and the asker discuss.
Ask to speak in turn: raise your open hand. Everyone will let the person speak when it's their turn.
I understand: make the "OK" sign.
I don't understand: raise your open hand to your chest, palm facing front, and move it side to side.
Please be louder: raise your open hand to your ear, palm facing front, so the moderator and/or speaker notices. This can indicate "please turn on your microphone".
Please be quieter: make the "shhh" sign with your pointer finger at your lips. This can indicate "please turn off your microphone".
Please stop/freeze/wait: hold up your closed fist, fingers facing front.
I'm typing in chat: show your hand and move your fingers as if you're typing on a keyboard.
Time check: point at your wrist. This means please be aware that there's a time limit coming up.