Dia is roughly inspired by the commercial Windows program 'Visio,' though more geared towards informal diagrams for casual use. It can be used to draw many different kinds of diagrams. (GPL)
Linux - FreeBSD - Windows
Draw is a vector graphics editor and is part of the LibreOffice office suite. (ZPL)
Linux - FreeBSD - Windows
Flow is an easy to use diagramming and flowcharting application with tight integration to the other Calligra applications. It enables you to create network diagrams, organisation charts, flowcharts and more. (LGPL)
Linux
3 applications