Visustin - Visustin is a flowchart generator to make you able to visualize your source code UML activity diagrams and flowcharts.
draw.io - Online diagramming application
Creately - The new interface for work to ideate, plan, and execute
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.
EazyStock - Smart demand forecasting and inventory optimisation software
PlantUML - PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams.