UMLGraph - UMLGraph is a professional automated drawing tool that allows the designers the declarative specification and drawing of UML class and sequence diagram.
Gephi - Gephi is an open-source software for visualizing and analyzing large networks graphs.
KeyLines - The JavaScript toolkit for graph visualization
SocNetV - Social Network Visualizer (SocNetV) is a cross-platform, user-friendly free software application for social network analysis and...
Dia - Dia is a GTK+ based diagram creation program for GNU/Linux, MacOS X, Unix, and Windows, and is released under the GPL license.
NodeXL - Home