1. 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.

  2. 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.

  3. Simplify and communicate complex information using data-linked diagrams.

  4. OmniGraffle is for creating precise graphics like website wireframes, an electrical system designs, or mapping out software class.

  5. D

    Dia is a GTK+ based diagram creation program for GNU/Linux, MacOS X, Unix, and Windows, and is released under the GPL license.

  6. FreeMind is a premier free mind-mapping software written in Java.

  7. PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams.

  8. XMind is a brainstorming and mind mapping application.