Gephi - Gephi is an open-source software for visualizing and analyzing large networks graphs.
Lampyre - Lampyre - an efficient data analysis and OSINT multi-tool for everyone.
Linkurious - Search and visualize your graph data through a simple web-based interface
Touchgraph Navigator - TouchGraph is the producer of data visualization software TouchGraph Navigator 2.
Maltego - Maltego is an open source intelligence and forensics application.
Cytoscape - Cytoscape Official Web Site