Blender - Blender is the open source, cross platform suite of tools for 3D creation.
KiCad - A Cross Platform and Open Source Electronics Design Automation Suite
FreeCAD - An open-source parametric 3D modeler
Proteus PCB design - Proteus PCB design combines the schematic capture and ARES PCB layout programs to provide a...
Sculptris - Sculptris: Enter a world of digital art without barriers.
EasyEDA - EasyEDA - Web-based EDA suite; runs in browser.