FreeCAD - An open-source parametric 3D modeler
Fritzing - Fritzing is an open-source initiative to support designers, artists, researchers and hobbyists to...
VARKON - Varkon is a very powerful parametric 2D/3D CAD, modeling and application development tool for...
Proteus PCB design - Proteus PCB design combines the schematic capture and ARES PCB layout programs to provide a...
Vectorworks - Vectorworks 2D / 3D CAD and BIM software for Mac or Windows provides one flexible solution for your entire design process. Sketch, model, and present with the ultimate software from start to finish.
LTspice - LTspice® is a high performance SPICE simulation software, schematic capture and waveform viewer with enhancements and models for easing the simulation of analog circuits.