With remote workshops we loose a bit of the non verbal communication we have during in-person workshops. But that's something we can easily fix.

When I have workshops with people who aren't super technical or geeky I teach them hand signals to use in front of their webcam. For example:
  1. A thumb up to say "I agree" or "I like this"
  2. Two thumbs up to say "This is so awesome!"
  3. A victory dance to say "Wow I looooooove this!"
  4. A thumb down to say: "I disagree"
  5. Two thumbs down to say: "This is really bad"
  6. The defeat dance to say: "This is total bullshit!!!"

Teaching such hand signals is usually also a pretty fun moment where you can help people relax a bit and understand that this will be a casual moment where everyone can share his emotions without fear.

When I have workshops with people who are a bit more geeky or technical I use the emoji reactions or the "raising hand" features of the video conferencing tools to get to the same result. 

Here too, it can be smart to explain at the start of the workshop which emoji will mean what during the workshop so that you have a common language.