SketchUp - 3D for Everyone
KiCad - A Cross Platform and Open Source Electronics Design Automation Suite
Autodesk Revit - Autodesk Revit is building information modeling software for architects, structural engineers, MEP engineers, designers, and contractors.
Fritzing - Fritzing is an open-source initiative to support designers, artists, researchers and hobbyists to...
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
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.