RemoteHQ - Real-time collaboration for distributed teams
Scribble Online Whiteboard - Scribble Online Whiteboard is an advanced collaborative whiteboard solution that allows you to draw the sketch using the web-based or mobile platforms such as iPad/iPhone and Android.
Diagrams for Mac - A diagram editor for visualizing structures and processes
Ryeboard - A practical and visual workspace for modern teams
Stately Viz - Visualize, simulate, and inspect your state machines
Whiteboard Team - Draw, explain and collaborate visually in real-time.