Neoclipse!

yEd is a powerful diagram editor that can be used to quickly create diagrams manually or import external data for analysis and auto-magically arrange even large data sets by just pressing a button. You can use yEd to quickly create flow charts, BPMN and UML diagrams, organization charts, mind maps, and many other kinds of diagrams, graphs, and networks. Choose from a wide range of highly sophisticated layout algorithms to automatically arrange diagrams in no time. An intuitive and visually appealing user interface makes creating diagrams fun. Once a diagram has been created, it’s easy to save, print, or export it to popular formats like PDF, SWF, EMF, SVG, JPEG, GIF, PNG, or HTML image maps. »

PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams. The generator can be run anywhere within JVM and integrated with various application such as wiki, text editor, IDE, programming language, documentation generator, and others. Mostly based on Graphviz. Can render various diagram syntax such as PlantUML, Dot, and Ditaa.

Graphviz is open source graph visualization software. It has several main graph layout programs. It also has web and interactive graphical interfaces, and auxiliary tools, libraries, and language bindings.

OmniGraffle can help you make eye-popping graphic documents—quickly—by providing powerful styling tools, keeping lines connected to shapes even when they’re moved, and magically organizing diagrams with just one click. Create flow charts, diagrams, UI and UX interactions, and more. Whether you need a quick sketch or an epic technical figure, OmniGraffle and OmniGraffle Pro keep it gorgeously understandable.

Gephi is an open-source software for visualizing and analyzing large networks graphs. Gephi uses a 3D render engine to display graphs in real-time and speed up the exploration. Use Gephi to explore, analyse, spatialise, filter, cluterize, manipulate and export all types of graphs.

Diagrammix is a tool for efficiently building attractive diagrams.

Cytoscape is an open source software platform for visualizing complex networks and integrating these with any type of attribute data. A lot of plugins are available for various kinds of problem domains, including bioinformatics, social network analysis, and semantic web.

Grapholite is a powerful online solution for the creation of flowcharts, org charts, mind maps, Venn charts, web site structures, etc. Can be used online and offline

Delineato - the italian word for "outline". Designed using the WYSIWYN paradigm - What You See Is What You Need - this carefully crafted application is targeted at creating simple diagrams, mind maps, brainstorming, to-do lists, architectural diagrams.A clutter-free interface allows you to concentrate and focus on the essence of your work.

KeyLines is a JavaScript toolkit used by developers to build powerful network visualization applications, quickly.

NodeXL is a free, open-source template for Microsoft® Excel® 2007 and 2010 that makes it easy to explore network graphs. With NodeXL, you can enter a network edge list in a worksheet, click a button and see your graph, all in the familiar environment of the Excel window.

As the easiest way to explore graph data, Linkurious technology helps you make sense of your data through a simple web-based interface. Companies can quickly visualize their data with Linkurious Enterprise or build their own application with the Linkurious SDK:

Online real time collaboration Flow chart software service. Flow charts made easy with online service Flowchart.com. A easy flowchart maker. A easy online diagram software maker

Graphity is a diagram editor that can be used to quickly and effectively generate drawings and to apply automatic layouts to a range of different diagrams and networks.

Online Charts Builder based on Google Charts API