Maybe this is sarcasm, buy Zoom has that exact feature.
I used that feature to "raise my hand" in my first ever Zoom meeting. The host didn't realize it until I raised my actual hand on video.
meet.jit.si has that feature. It seems really superior to Zoom (no account needed, links in natural language, great UI, good sound/video quality), I don't know why more people don't use it.
Cisco meeting software has this and its almost never used.