Network Weathermap - Network Weathermap is a robust and open-source network visualization solution that enables you to use network statistics for creating live network maps.

UCINET - UCINET for Windows is a software package for the analysis of social network data.

Gephi - Gephi is an open-source software for visualizing and analyzing large networks graphs.

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Pajek - Pajek is a lightweight solution developed from scratch by an extraordinary team of developers for the purpose of Large Network Analysis.

Graphviz - Graphviz is open source graph visualization software. It has several main graph layout programs.