LucidChart - LucidChart is the missing link in online productivity suites. LucidChart allows users to create, collaborate on, and publish attractive flowcharts and other diagrams from a web browser.

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

draw.io - Online diagramming application

Wandora App - Wandora is a general purpose information extraction, management and publishing application based on...

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.

Linkurious - Search and visualize your graph data through a simple web-based interface