Minzel - Minzel is a beautiful and free mindmapping tool built for creatives and gives you the power to...
Wireflow - Create beautiful flowcharts
TiddlyMap - An interactive concept- and mind-mapping plugin for the personal note-taking software TiddlyWiki based on the Vis.js library. It's free and open-source!
Zen Flowchart - The simplest tool to create flowcharts
Mindmaps.app - Mindmaps.app is a browser-based mind mapping software that you can use to generate well-ordered mind maps.
Vexlio - Instantly create precise, beautiful diagrams