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
Sculptris - Sculptris: Enter a world of digital art without barriers.
Proteus PCB design - Proteus PCB design combines the schematic capture and ARES PCB layout programs to provide a...
ZBrush - ZBrush is a digital sculpting and painting software solution.
QUCS - Qucs, briefly for Quite Universal Circuit Simulator, is an integrated circuit simulator which means you are able to setup a circuit with a graphical user interface (GUI) and simulate the large-signal, small-signal and noise behaviour of the circuit.