Free drawing software for Windows, Mac OS X, and Linux
Dia Diagram Editor is free Open Source drawing software for Windows, Mac OS X and Linux. Dia supports more than 30 different diagram types like flowcharts, network diagrams, database models. More than a thousand readymade objects help to draw professional diagrams. Dia can read and write a number of different raster and vector image formats. Software developers and database specialists can use Dia as a CASE tool to generate code skeletons from their drawings. Dia can be scripted and extended using Python.
A full featured cross-platform image library
Developer's Image Library (DevIL) is a cross-platform image library utilizing a simple syntax to load, save, convert, manipulate, filter and display a variety of images with ease.
BirdFont is a font editor which lets you create vector graphics and export fonts in TTF, EOT and SVG format. Binary releases are available from the website.
Vector-graphics editor/animator (Lazarus, under GPL) for rotoscoping animations.