LibreCAD - An open source 2D CAD application for Windows, Apple and Linux.
NttCAD - Free 2D/3D CAD software, easy to use and multi-platform
KediCAD - CAD/CAM/ FEA software for Linux
TYCAD - TYCAD is a application for computer aided drafting (CAD) in two dimensions (2D).
DualCAD - Freeware cad application that handles the basic needs of most Microstation users
DraftSight - Discover Dassault Systèmes®' DRAFTSIGHT™ Professional CAD software that lets you create, edit, view and markup any kind of 2D drawing. Learn more here.