Zen Flowchart - The simplest tool to create flowcharts
Diagrams for Mac - A diagram editor for visualizing structures and processes
Octopus.do - Build your website structure in real-time and rapidly share it to collaborate with your team or clients. Start prototyping websites or apps instantly.
Diagrammm - Fundamentals on data visualization
Scheme Flowcharts - A huge pack of layouts for UX prototyping
Wireflow - Create beautiful flowcharts