Digital Tools

Game Creation Tools

• Adventure Game Studio
• Blitz Basic
• Dark Basic
• DevKitPro - Ideal for homebrew development for portable gaming consoles like Nintendo DS, Sony PSP and Game Park GP32.
• Emergence Basic - A little cluttery syntax, but in the root sense of basic. Compiles binaries.
• FlashDevelop - Independently develop scripts and applications for Flash. Now with Actionscript 3.
• Games Factory - Awful title, but similar to Game Maker. Suitable for fast prototyping and 2D games. Some pretty fun games were made with that.
• Game Maker - Prototyping of games was never easier.
• Pure Basic - This one is my favourite under the alternative basics. Compiles small and fresh binaries and is very precise.
• Scrolling Game Development Kit
• Unity 3D - Unlike the title implies you can also make 2D games with it, that are also browser ready with the Unity Web Plug.

3D Engines

• Blade 3D
• C4 Engine - Looks good and got good reviews. Haven't tried it myself.
• Crystal Space - Free cross-platform software development kit for realtime 3D graphics.
• Unity 3D - A 3D development environment, even browser-compatible with the Unity Web Plug.

Libraries

• Allegro
• Box2D - Box2D is a 2D rigid body simulator / physics engine for games.
• CeGUI - A library for making Graphical User Interfaces in games. Supports multi-plattform and is xml-data driven.
• Clanlib - I think this is a "standard" or "classic" when messing with 2D games and engine modeling. Fun, but like everything that deals with C/C++ sooner or later you begin to fiddle.
• Lua - Very cool scripting language especially for doing game maps, game logic or just to fool around. There is also a special Lua for the Sony PSP, check: luaplayer.org
• PAlib to make use with DevKit Pro for Nintendo DS development.
• SDL - Also a certain standard. Makes programming of window machines a little bit easier, but still complicated in my opinion. I didn't get deep into this, thanks to the Gates guys, etc.

Graphic Artwork Tools

• Chili - Tileeditor and export, edit and convert grafics into the GBA format. For homebrewers on Windows.
• Farbrausch Werkkzeug - Procedural textures for the artist and non-coders.
• GraphicsGale
• Mappy - Tile-, Sprite and Map-Editor with good code integration to game projects written in C/C++ or Lua.
• Tile Studio - Solid Tile-, Sprite and Map-Editor.

Helpers

• Caprect - Fast and easy to use tool for making screenshots on Windows.
• Css4you - Comprehensive css-reference, that also delivers a compatibility list of different browsers for each css-tag. It's in German, but the compatibility list should be readable for all. A complete English reference is Htmldog.
• Css Reference - at W3Schools. Simple and good.
• Ditto - Very, very useful tool. A customizable multi copy-buffer.
• IRC - Stay connected to your peers with the IRC text chat. IRC maybe made more teams and friendships than any other application in the world.
• Notepad++ - Lightweight multi-purpose coding IDE. Best directly install also the light explorer plug-in and if you are also into web-applications the ftp-synchronize plug-in.
• Pixie - A multi-purpose colorpicker. Also look http://www.literatecode.com/software. Similar tool is Colpick2.
• SFXR - Soundeffects for everybody. A neat tool that generated great retro-style game sounds in a blink.
• Vector Magic - Easy and free to use online vectorizing tool to apply on logos, graphics and other stuff, for example to use it in point-and-click adventure games or to add your game some surrealistic style or easily get into strange colorings. Can reduce filesize and/or make graphics available as forms and paths in different context.

Special Interest

• LDraw Lego 3D Tool - Library for doing Lego-style.
• Processing - Best way to get into creative coding.
• SodaPlay - Hard to describe, just check it out.