I guess the Google Jamboard whiteboard app has been around for 4 years. I think it is tied to a hardware product that you could use with Jamboard that was also (for clarity?) called Jamboard. Basically it is an alternative to using a Googlesheet or Googledoc to collaborate. I learned about it in a professional development session about something else.
You can open a Jamboard by going to jamboard.google.com when logged into your google account. Select the orange plus to create a new Jamboard. You can share view or edit links with participants in a class or meeting. Make sure to change the settings to anyone with the link can edit for maximum participation. Or, if you know everyone’s Google handle you can invite them individually.
In a jamboard you can post, edit, and rearrange sticky notes. This could be helpful for brainstorming and creating commonalities. You can write with various markers in assorted colors. You can erase. You can import a photo. You can add text. You have access to a laser pointer in case you are sharing this in Zoom, Teams, or another teleconferencing product.

I have used it to help brainstorm and gather ideas for Local 1650 social events and to take notes on a CTEI Session called Teamwork Tuesdays this week (view only link). I am not sure if I am using it so much because it is new and the infatuation will wear off. I do however see uses for this that shared spreadsheets and documents might be harder to replicate. You can rearrange and group the notes easily and visually for instance. You could then use text or a pen to label the larger category. You could use it to vote (somewhat openly).
I suspect many of you already knew about this one. The rest of you might want to check it out.