LibreCAD - An open source 2D CAD application for Windows, Apple and Linux.
progeCAD Smart - progeCAD Smart! Free version of progeCAD, the IntelliCAD alternative to AutoCAD
Piglet Drawing Editor - 2-D engineering drawing editor that supports hierarchical object description
DraftSight - Discover Dassault Systèmes®' DRAFTSIGHT™ Professional CAD software that lets you create, edit, view and markup any kind of 2D drawing. Learn more here.
QCAD - QCAD is an application for computer aided drafting in 2D.
nanoCAD - nanoCAD is a pro-grade 2D CAD system with native DWG support and full customizability.