Inkscape is a free and open source professional quality vector graphics editing software founded by Nathan Hurst in 2003 and is capable of running on Windows, Linux and Mac OS X (requires X11/XQuartz to support on Mac OS X).
FireAlpaca is a Japanese painting and illustration software and is free and open source.
This neat and user-friendly piece of freeware is both Windows and Mac OS X compatible and is great for creating illustrations, digital paintings or just simple sketches and doodles.
The software officially comes in a variety of alternative languages such as Chinese (both traditional & simplified forms), English, French, German, Korean, Portuguese, Russian and Spanish.
GIMP (abbreviation of GNU Image Manipulation Program) is a freely distributed raster graphics editor that is capable of performing tasks such as photo retouching & editing, image composition, drawing and image authoring. The software was initially released in 1996 and was developed by duo Spencer Kimball & Peter Mattis.
Over the years, GIMP has developed a fairly avid community from amateur to professional artists to open source fans and now has an on going online magazine.
It runs on Mac OS X, Linux and Windows and comes in a variety of languages.
Blender is a piece of freeware that specializes in 3D graphics and animation. It has been used among both amateurs and professionals in the industry with Spiderman 2 being the first large professional project to use Blender, primarily by the storyboard department for animatics and pre-visualizations.
The program is compatible with Windows, Linux and Mac OS X.
Scribus is an open source desktop publishing program available for GNU/Linux, Windows and Mac OSX.
Scribus is designed for layout, typesetting and preparing files for image setting equipment to a professional standard. The program is also capable of producing animated and interactive PDF presentations and program is an ideal freeware application to create layouts for small newspapers, magazines, newsletters, posters and books etc.
It was initially released on 26 June 2003.
FontForge is free full-featured typographic and letterform editing software, similar to InDesign and supports all common font formats . In the program, the user is capable of producing their own typefaces and letterforms.
FontForge was first founded by George Williams and was initially as PfaEdit from 2001 to 2004 and was primarily developed by him until 2012.
This program is compatible with several operating systems, including Windows, Mac OS X and GNU/Linux
Processing, released since 2001, is a programming language with a development environment and an online community and following. Processing has been used to promote software within visual arts and visual literacy of technology. It was first created as a software sketchbook of sorts, yet has evolved to be used as a development tool for even professional users.
Today, it is still used for prototyping, learning and professional production by hobbyists, professional workers, students, designers, artists and researchers and so on.
It is available for Windows, Mac OS X and GNU/Linux
Arduino is a an open-source electronics platform based on flexible easy to use hardware and software. It manages to create a hybrid between physical computing and interactivity as the computing & coding world and physical world combine by using elements such as sensors, indicators and actuators, etc
It has grown quite a following and online community and many people work with this software as a hobby as well as for educational projects.