Lucidchart is a web-based application to draw diagrams.

PlantUML is an open-source tool allowing users to create UML diagrams from a plain text language.

Umbrello UML Modeller is a free software UML diagram tool available natively for Unix-like platforms and Windows.

Diagrammix is a tool for efficiently building attractive diagrams and flowcharts.

ConceptDraw PRO is diagramming software used to create business graphics, including ConceptDraw Flowcharting Suite.

StarUML is an opensource UML tool.

Nevron Draw is a software for creating flowcharts and diagrams.