Inkscape - Inkscape is a free, open source professional vector graphics editor for Windows, Mac OS X and Linux.
Framer - 🔥 Design real websites right on the canvas.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
MontageJS - MontageJS framework is a platform to develop and create single page applications (which load single HTML page and dynamically update the app as the user puts in inputs or requests or interacts with the page.) with ease.
Sculptris - Sculptris: Enter a world of digital art without barriers.
Marvel - Turn sketches, mockups and designs into web, iPhone, iOS, Android and Apple Watch app prototypes.