An award-winning drawing program for children of all ages
A simple LaTeX {picture} drawing tool
very good CAD software
2D CAD for precise drawing
The Pencil Project's unique mission is to build a free tool
Vector drawing program for LaTeX using PSTricks
Simple and intuitive 2D vector drawing for electronics and not only.
Syntax Tree Drawing Software (Linguistics)
Simple drawing program for Linux
Free drawing software for Windows, Mac OS X, and Linux