These are some of my go-to agreements for online engagements. I believe that having some agreements like these allows participants to share responsibility for the well-being and direction of the group and cultivates a brave space. Note that I am not calling these Conversation Guidelines, because the word "guidelines" doesn't evoke that sense of shared responsibility. I also do not call these Ground Rules, because the word "rules" evokes a sense of command and control. I use "agreements" because I invite all to agree to upholding them, generally after there has been some thoughtful review and refinement by the group if they didn't create the agreements themselves.
When you are holding space for people who are going to be in conversations that invite vulnerability and courage, having agreements like these are even more important. And you'll want to spend some time on them too perhaps starting with inviting people to share what they need in order to be brave. Notice, I did not say "safe" because that word evokes a sense of comfort and conversations that invite vulnerability and courage come with some discomfort.
Once agreements are made, you can include them in your invitation communications, reminder communications, make them part of your Zoom waiting room customized message, repeat them at the start of gathering, and copy them into the chat before engaging in a dialogue in the large group or before sending people into breakout rooms. Don't just flash them on the screen once and move on. It is helpful to keep them front of mind and remind everyone of their shared responsibility to uphold them.