Diagrams for Mac - A diagram editor for visualizing structures and processes
Sketchboard.io - Visual Remote Teamwork. Solve problems and create ideas on endless whiteboard with your teammates by sketching.
Screenshot Flow - Super fast app diagrams to communicate design
Limnu - Sketch, share and collaborate with your team
Wireflow - Create beautiful flowcharts
Draw.Chat - Anonymous real-time whiteboard with text and video chat.