UML Designer - UML Designer provides a set of common diagrams to work with UML 2.5 models.
UMLGraph - UMLGraph is a professional automated drawing tool that allows the designers the declarative specification and drawing of UML class and sequence diagram.
Diagramo - Diagramo is an online flowchart software - diagrams (create, edit and share)
Dia - Dia is a GTK+ based diagram creation program for GNU/Linux, MacOS X, Unix, and Windows, and is released under the GPL license.
ARIS Express - ARIS Express is based on the proven ARIS methodology and industry standards.
yEd - 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.