Zen Flowchart - The simplest tool to create flowcharts
vym - VYM (View Your Mind) is a tool to generate and manipulate maps which show your thoughts.
Speedy Flowchart - For developers to be able to draw flowcharts, convert them into text files and add them into there code or readme quite quickly.
Freeplane - Freeplane is a powerful and free software for building mind maps.
Wireflow - Create beautiful flowcharts
SuperNotecard - Introducing SuperNotecard. SuperNotecard is an online writing tool that features virtual notecards to help arrange facts or scenes, track details, organize paragraphs, and clarify your composition process.