LucidChart - LucidChart is the missing link in online productivity suites. LucidChart allows users to create, collaborate on, and publish attractive flowcharts and other diagrams from a web browser.
PlanoHero - PlanoHero - is a cloud service for automating planogramming processes, analyzing store plans and planograms.
draw.io - Online diagramming application
Visustin - Visustin is a flowchart generator to make you able to visualize your source code UML activity diagrams and flowcharts.
yEd - yEd is a free desktop application to quickly create, import, edit, and automatically arrange diagrams. It runs on Windows, Mac OS X, and Unix/Linux.
SmartDraw - Instead of starting with a blank screen, SmartDraw gives you the exact template you need.