FreeCAD - An open-source parametric 3D modeler
Sketch - Professional digital design for Mac.
SketchUp - 3D for Everyone
Inkscape - Inkscape is a free, open source professional vector graphics editor for Windows, Mac OS X and Linux.
LibreCAD - An open source 2D CAD application for Windows, Apple and Linux.
Adobe Photoshop - Adobe Photoshop is a webtop application for editing images and photos online.