FreeCAD - An open-source parametric 3D modeler
CODESYS - CODESYS - the IEC 61131-3 programming system.
SketchUp - 3D for Everyone
EPLAN Electric P8 - CAE software solution for project planning, documentation and administration of electrotechnical automation projects.
LibreCAD - An open source 2D CAD application for Windows, Apple and Linux.
E3.series - Electrical design software that facilitates an efficient and accurate design and manufacturing process for electrical and fluid planning, cable planning, wire harness and cabinet layout.