Garbage - In my opinion, poor quality Whiteboard paint, do not buy
Witeboard - A real-time whiteboard for your team. No signups required.
Ziteboard - Ziteboard is an zoomable online whiteboard that lets team to collaborate in real-time.
Miro - Scalable, secure, cross-device and enterprise-ready team collaboration tool for distributed teams. Join 2M+ users & 8000+ teams from around the world.
Idea Paint - Create a usable, interactive space on any flat surface
Jamboard - Interactive Business Whiteboard | G Suite