yEd Graph Editor
Free
yEd is a free general-purpose diagramming program with a multi-document interface.
Graphviz
Open Source
Graphviz (Graph Visualization Software) is a package of open-source tools initiated by AT&T Labs Research for drawing graphs specified in DOT language scripts…
PlantUML
Open Source
PlantUML is an open-source tool allowing users to create UML diagrams from a plain text language.
Compare Gephi with alternatives
Compare yEd Graph Editor and Gephi and decide which is most suitable for you.