i don't really think that at this point, we need an index this big for finding Open Source Software, but i keep updated this list for all my Deviant Art watchers, that not always care to look at it because they feel invincible with Adobe's Flash, Photoshop and 3D Studio Max (they are pretty good, i was very used on them when i had XP), apart from their regular commercial software i'm always trying to make an invitation to FOSS because in most cases, they does not ask nothing to commercial ones.
-Ubuntu Studio: Let Your Creativity Fly...
My current Operative System, i can say is maybe the most impressive attempt i ever saw for transform an entirely OS into a full-top-high level-art center, a very complete suite with most of the tools listed below perfectly integrated in a Distro, has nice wallpapers, options, look, hell, what can i say, 100% customizable, you must give it a try! (attention, since you are about to install an entirely new OS, i strongly suggest you to read carefully how to do it, also you might like to have your original OS and plus this new one, this is called 'dual boot' read more on google)
-GIMP: GNU Image Manipulation Program
This is what you can call an 'equivalent' of the commercial software Photoshop, since i changed to Linux, Ubuntu and Mandriva, i've been using this software, and i feel pretty comfortable with it. GIMP also has a great plugin database to enhance it functionality, check the entire site, believe me is worth of it. Also pay attention, GIMP is not better or worst than Photoshop, they are both different but with the same capabilities for those who seek professional working.
-MyPaint: A fast and easy open-source graphics application for digital painters
You work on your canvas with minimum distractions, bringing up the interface only when you need it.
MyPaint comes with a large brush collection including charcoal and ink to emulate real media, but the highly configurable brush engine allows you to experiment with your own brushes and with not-quite-natural painting
-BLENDER: The free open source 3D content creation suite
It's a great 3D rendering, animation, modeling tool and it even have it own game engine, that let's you make games (XD), it interface is unique and customizable, it is also tricky but with a little practice you will find is like a candy, personally i prefer Blender to Autodesk Maya Linux, simple by the fact that Blender tends to be agile and professional, but still simple.
-InkScape: An Open Source vector graphics editor
I also used to handle Adobe Illustrator and i liked it, now i use InkScape, and the description does not lie, is capable of the same that any Corel or Adobe product may offer, stick with this one for your vector based graphics, you will enjoy what can make for you
-Synfig Studio: A tool for producing feature-film quality animation
If you are like me, that enjoy animation as much as drawing, this tool is for you, easy intuitive and fast but tricky sometimes, with great effects and advanced functions, it's a great innovation for the few free animation programs that does exist nowadays, check the website as most of the GNU programs, you will always find help and tutorials for you to use
-KTooN: 2D Animation Toolkit
If you have used Macromedia Flash (Adobe Flash is not like Macromedia Flash) then you will find no problems using Ktoon (and even if you have never touched any animation software), Latest news is that the project has resurrected and i have keep track of the site since it changed it main page for an announce telling that 2010 is the year of Ktoon, seem the site would be online some of this days so i keep an eye on it, originally, KToon was my favorite tool for animations (because i couldn't install flash on linux) their last version can be found on repositories, a little buggy on Debian systems, haven't tried with Mandriva yet, but for those who *windows* can follow this link: http://mac.softpedia.com/get/Graphics/KToon.shtml
give it a try, i can guarantee you hours of entertaining animation process (well.... at least i did have them before Synfig Studio) curious, not related to any KDE4/QT component despite the 'K' on it's name, current GUI is on GTK
-StickyPy: A professional stick figure animation program written in Python and PyGame
I would suggest don't get fooled by the lack of creativity of the design in the UI, this is actually a good program that requires Python and PyGame libraries, the advantage of Python is that can run on almost any Operative System as long as it has installed Python, which can be downloaded from the page with the same name 'www.python.org', but also i will strongly suggest it windows counterpart 'Pivot' because will run smoothly on windows xp-vista-7 as it has a native integration with that OS, here is the WIKI http://en.wikipedia.org/wiki/Pivot_Stic ... rnal_links
and this is the page which has the most used version of that program (based in Youtube's videos) http://j13.digitaljoven.com/#dls
-LiVES: Is a Free, Open Source video editor *and* a VJ tool
The best video editing software i've seen, it has copy-paste, frame rate, real time filters and effects, quality setting and many more things that i don't understand since i'm not in the video editing world, pretty exiting anyway and plus, newer UI which makes it more friendly with the user.
-Kdenlive: Free and open-source video editor for GNU/Linux and FreeBSD
Kdenlive is an intuitive and powerful multi-track video editor, including most recent video technologies. Our software is completely free, in all sences of the expression, as defined by the GNU foundation. Using Kdenlive is investing in a community driven project, which aims to establish relationships between people in order to built the best video tools. Also, for add something of my own opinion, it's actually a very good tool, i used it to export some animations importing png files, just a few clicks and you can make your own video with sounds and things.
-LMMS: A free cross-platform alternative to commercial programs
One of the best music production and composition software known around is FL Studio, well, this is what you can call a Linux FL, and is even compatible with the native installation of FL itself, a great tool that you can't see every day, and is X-Platform meaning that even Windows user can taste it, give it a damn try, is and order and i demand it!.
-Avidemux: A free video editor designed for simple cutting, filtering and encoding tasks
Why should i bother to put a lighter video editor when i wrote about LiVES some lines back? because this one is also a good editor and can be used for fast video editing, light things that doesn't deserve to open LiVES, even tough, still one of the best video editors due to it's functionality and simplicity
-Ardour: Digital Audio Workstation
This software remembers me to a windows's program called 'Live 5' nothing to be with 'LiVES' btw, it's a multi-track song editor/producer, many features, if you keep down with music composition, i demand you to try this one.
-Jokosher: A simple yet powerful multi-track studio
Yep, the description says it all, i have an electric bass, and this software is pretty useful combined with real instruments, even that, you can try to put you own sound files and things, try it out
-Audacity: Is a free, open source software for recording and editing sounds
mm... maybe the best comparison i can make of this software is with Sony Sound Forge, i edited some songs with this program and works good, if you have some mp3 you want to mess with, use Audacity
-K3D: Is free-as-in-freedom 3D modeling and animation software
Pretty descent 3D Editor, i like more Blender, but i tried this one too, not bad tough.
-Wings 3D: A subdivision modeler inspired by Nendo and Mirai from Izware.
Nothing special about this one, i included this program because it has a native compatibility with PovRay Modeler, a 3D scene renderizer with a high level of quality that makes worth to try Wings 3D
-Krita: A graphics application for everyone who wants to get creative with images
This is the true port of Photoshop into GNU/Linux world, the interface and options, all seems to be very like Photoshop, still i prefer GIMP, Krita is part of the free Office Suit for KDE named 'KOffice', a port of Krita for windows is available, tough is not an official port.
-Cinelerra :A video editor and compositor for Linux
One of the best video editors, like LiVES is pretty full of options, plugins, effects and edition tools, i played a bit with it and is pretty fun to work with it, perhaps is a shame that is only available for Linux (not for me, i use Linux)
-CreaToon® is a powerful software solution for the PC to create 2D animation in the cut-out style.
No idea what it does, i'm downloading it right now, but looks promising, can it do something that Synfig can't? XD i doubt it.
---------------------------------------------------------------About the GNU: General Public LicenseAbout the Open Source Software
I also suggest you to look at Source Forge
, the life is easy when you know where to look at.