LibreCAD - An open source 2D CAD application for Windows, Apple and Linux.
FreeCAD - An open-source parametric 3D modeler
KediCAD - CAD/CAM/ FEA software for Linux
DraftSight - Discover Dassault Systèmes®' DRAFTSIGHT™ Professional CAD software that lets you create, edit, view and markup any kind of 2D drawing. Learn more here.
High Design - HighDesign software is for architectural design, engineering, MEP, detailing, and construction.
FreeDraft - Full-featured 2D DWG, DXF compatible CAD Software