LibreCAD - An open source 2D CAD application for Windows, Apple and Linux.
DualCAD - Freeware cad application that handles the basic needs of most Microstation users
QCAD - QCAD is an application for computer aided drafting in 2D.
High Design - HighDesign software is for architectural design, engineering, MEP, detailing, and construction.
TYCAD - TYCAD is a application for computer aided drafting (CAD) in two dimensions (2D).
DraftSight - Discover Dassault Systèmes®' DRAFTSIGHT™ Professional CAD software that lets you create, edit, view and markup any kind of 2D drawing. Learn more here.