https://github.com/joelparkerhenderson/ground_rules

Hand signs can be helpful for video conferencing, for large meetings, for loud environments, and for people who are hard of hearing.

Vote yes: thumb up.

Vote no: thumb down.

Vote maybe: thumb sideways.

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.

Clarification ASAP: make the letter "C" sign. This means everyone pause as soon as possible, so the facilitator can do clarification.

Ask to speak in turn: raise your open hand. This means everyone will let the person speak when it's their turn.

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.

Time check: point at your wrist. This means please be aware that there's a time limit coming up.

Time out: make the time out sign. This means conversation stops, and the facilitator takes over.

... These ground rules and hand signs work well for us in practice, and may be helpful to you. Your mileage may vary. Constructive feedback welcome. PMs are welcome - my contact info is in my HN link.