Inkscape - Inkscape is a free, open source professional vector graphics editor for Windows, Mac OS X and Linux.
Minzel - Minzel is a beautiful and free mindmapping tool built for creatives and gives you the power to...
Sketch - Professional digital design for Mac.
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!
Affinity Designer - Professional creative software, exclusively for Mac.
MindNet - MindNet is an effective productivity and learning tool that allows you to take notes, write down ideas, learn, brainstorm your mind, and much more in intuitive graphical mind maps.