UCINET - UCINET for Windows is a software package for the analysis of social network data.
Lampyre - Lampyre - an efficient data analysis and OSINT multi-tool for everyone.
Gephi - Gephi is an open-source software for visualizing and analyzing large networks graphs.
Linkurious - Search and visualize your graph data through a simple web-based interface
Pajek - Pajek is a lightweight solution developed from scratch by an extraordinary team of developers for the purpose of Large Network Analysis.
Maltego - Maltego is an open source intelligence and forensics application.