Miro.com is "The online collaborative whiteboard platform to bring teams together, anytime, anywhere."
It allows multiple participants to simultaneously interact on a common screen. It has an infinite canvas, which means you can build some really cool designs and create amazing activities.
My friend and business partner Rakshith is doing full-fledged 3 hour long sessions entirely on Miro with no presentation tools. He even ditches Dextr.io (our own presentation tool) and uses Miro instead in some of these sessions.
To be fair, I have not used it that much as a facilitator. But I have been a part of many sessions where other facilitators have used the tool absolutely brilliantly. My experience as a participant and a learner was really fun. I felt highly involved and connected to the session and to the other participants.
The free version is pretty good, and the paid version is very powerful, while being highly affordable. I strongly recommend you give it a shot.