Microsoft Office Visio!

Lucidchart is an online diagram and flowchart software that supports Microsoft Office Visio import and can work on any operating system. The easiest way to draw flowcharts, wireframes, UML diagrams, network diagrams, mind maps, iPhone mockups, site maps and more. Work together in real time with your team and clients! Along with the online version, Lucidchart also has a downloadable solution that runs on Mac, Windows and Linux; this enables offline editing at any time! »

draw.io is a free online diagram drawing application for workflow, BPM, org charts, UML, ER, network diagrams. No login or registration are required and features include the ability to save locally (including svg), a range of stencils, .vsdx, Lucidchart and Gliffy import and real time diagram sharing.

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. »

Pencil is a standalone app or Firefox extension that lets you create diagrams or UI mockups. It doesn't have collaboration/multi-user features.

Draw lets you produce anything from a quick sketch to a complex plan, and gives you the means to communicate with graphics and diagrams. With a maximum page size of 300cm by 300cm, Draw is a an excellent package for producing technical drawings, general posters, and much else.

Lucidchart is an online diagram and flowchart software that supports Microsoft Office Visio import and can work on any operating system. The easiest way to draw flowcharts, wireframes, UML diagrams, network diagrams, mind maps, iPhone mockups, site maps and more. Work together in real time with your team and clients! Along with the online version, Lucidchart also has a downloadable solution that runs on Mac, Windows and Linux; this enables offline editing at any time! »

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.

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.

Google Drawings, part of Google Drive , allows users to collaborate creating, sharing, and editing images or drawings. It can be used for creating charts, diagrams, designs, flow-charts, etc. It contains a subset of the features in Google Drive - Slides but with different templates. Its features include laying out drawings precisely with alignment guides, snap to grid, auto distribution, and inserting drawings into other Google documents, spreadsheets, or presentations. »

Draw, part of the Apache OpenOffice suite, is a graphics editor that gives you the tools to communicate with visuals and diagrams. With a maximum page size of 300cm by 300cm, Draw is powerful tool for posters, graphs, charts, and more.

Creating flowcharts, organizational charts, business diagrams, science illustration, network diagrams, mind map and lots more. Free Examples Download.

Create deep visual documents, adaptable and multi-level diagrams, flowcharts, concept maps, mind maps and models.Users can:- Define their own types of nodes and connectors, to reuse nomenclature, symbols, details structure.- Add Details to your Ideas (attachments, links, custom-fields, tables)- Ideas can have a whole new diagram inside (multilevel/composable)- Can generate a report for the whole Composition document.- Reports are exportable as PDF/XPS and to HTML.- Collapse/Expande supertrees or subtrees of connected ideas.- Add Markers to your ideas (predefinables).- Include rich descriptions, versioning, complements (stamps, regions/boundaries, call-outs, notes, legends, cards). »

UMLet is an open-source UML tool with a simple user interface: draw UML diagrams fast, export diagrams to eps, pdf, jpg, svg, and clipboard, share diagrams using Eclipse, and create new, custom UML elements.

This software empowers users to construct, navigate, share, and criticize knowledge models represented as Concept Maps. The toolkit is platform independent and network enabled, allowing the users to build, and collaborate during the construction of concept maps with colleagues anywhere on the network, as well as, share and navigate through others models distributed on servers throughout Internet.