A list of game development resources to make magic happen. This list is a copy from others lists originated from reddit and some other wiki pages. Feel free to fork and leave your contribution.
*Great graphics placeholders and tools to turn that squared game into a picasso painting *
- Openstock Project - Modern 2D vector style game assets for indie developers, students, hobbyists & professionals – free personal & commercial licences.
- Reiner's Tilesets - A blog with free 2D and 3D graphics.
- SpriteLib - a collection of static and animated graphic objects (also commonly known as sprites).
- OpenGameArt - a media repository intended for use with free software game projects.
- Games-Icons Set - free icons for your games.
- Iconmonstr - Another free icons resource for your games.
- Vecteezy - Free Vector Art.
- OpenClipart - Collection of free cliparts.
- Tree Generator - An Online tree generator.
- CGTextures - A large collection of textures.
- TextureKing
- PlainTextures
- Sketchfab - Publish & embed interactive 3D models.
- Gunpoint-3D - specialized resource dedicated to armored military weapons, the modern and used in world wars.
- ShoeBox - ShoeBox is a free Adobe Air based app for Windows and Mac OSX with game and ui related tools. Each tool uses a drag and drop - or clipbord interaction for a quick workflow.
- TexturePacker - Great spritesheet creation editor.
- GraphicsGale - Animation graphic editor easy to use.
- Spritesheet Preview - A simple and free tool to preview sprite sheets
- Aseprite - animated sprite editor & pixel art tool.
- PiskelApp - Free Online Pixel Art and Animated Sprite Tool.
- TinyPNG - Advanced lossy compression for PNG images that preserves full alpha transparency.
- PNGGauntlet - Smash PNGs for faster sites
- FilterForge - A plugin for Adobe Photoshop that allows you to build your own filters.
- PixPlant - PixPlant is a smart 3D texturing tool that creates high quality normal, displacement, specular maps and seamless textures from photos.
- STG - a tool for creating professional seamlessly-tileable textures from photographs quickly and easily.
- Famistu Chibi Maker - A tool to make the famous chibi chars and use in your game.
- Loose Leaf
- Charas - Charas is a charset generator for RPG Maker.
- Tiled - free, easy to use and flexible tile map editor.
- ArrayPainter - Array Painter is the easiest and fastest way to make 2D arrays ready for copy pasting into your own program.
- AutoTileGen - AutoTileGen is an automatic tileset generator for 2D game terrains.
- Spriter - Modern tool for sprite animation.
- Spine - Spine is dedicated to 2D animation, providing an efficient workflow both for creating amazing animation and for integrating it into your games.
- Inkscape - An open-source vector graphics editor similar to Adobe Illustrator, Corel Draw, Freehand, or Xara X.
- Krita - Krita is a KDE program for sketching and painting, offering an end-to-end solution for creating digital painting files from scratch by masters.
- Gimp - GNU Image Manipulation Program. It is a freely distributed piece of software for such tasks as photo retouching, image composition and image authoring.
- Ormr - Ormr is a fast, light-weight, cross-platform procedural graphics editor.
- Paint.NET - Paint.NET is free image and photo editing software for PCs that run Windows.
- PyxelEdit - Pixel art editor designed to make it fun and easy to make tilesets, levels and animations.
- Pickle - Another Pixel art Editor.
Set of game frameworks, engines and platforms
- Construct 2 - an HTML5 game maker, meaning you are not actually writing JavaScript. Instead, you use actions, events and conditions to do the heavy lifting.
- ImpactJS - Impact is a JavaScript Game Engine that allows you to develop stunning HTML5 Games for desktop and mobile browsers.
- PixiJS - is a newcomer HTML5 game renderer - first released in early 2013. A main appeal of the engine is its use of WebGL for faster performance. If WebGL isn't supported, the engine falls back to standard canvas.
- GameMaker - GameMaker accommodates the creation of cross-platform video games using drag and drop or a scripting language known as Game Maker Language, which can be used to develop more advanced games that could not be created just by using the drag and drop features.
- Phaser - free and fast 2D game framework for making HTML5 games for desktop and mobile web browsers, supporting Canvas and WebGL rendering.
- Cocos2D - graphic library for games and multimedia, for python language
- Lycheejs - JavaScript Game library that offers a complete solution for prototyping and deployment of HTML5 Canvas, WebGL or native OpenGL(ES) based games inside the Web Browser or native environments.
- MelonJS - open source light-weight HTML5 game engine.
- LimeJS - HTML5 game framework for building fast, native-experience games for all modern touchscreens and desktop browsers.
- EnchantJS - A simple JavaScript framework for creating games and apps.
- voxel.js - voxel.js is a collection of projects that make it easier than ever to create 3D voxel games like Minecraft all in the browser.
- Stencyl - a game creation platform that allows users to create 2D video games for computers, mobile devices, and the web.
- RPGMaker - series of programs for the development of role-playing games.
- FlashPunk - free ActionScript 3 library designed for developing 2D Flash games.
- Flixel - an open source game-making written in ActionScript3.
- Box2D - A 2D Physics Engine for Games.
- p2.js - JavaScript 2D physics library
- LÖVE - Lua 2D Game Engine.
- SpriteKit - iOS/Mac 2D Game Engine.
- NodeBox - a family of Python tools to create generative design.
- PyGame - a 2D game engine in Python.
- Processing - Processing is a programming language, development environment for artists, designers, researchers.
- Unity 3D - A development engine for the creation of 2D and 3D games and interactive content.
- UDK - the game engine technology developed by Epic Games.
- Havok Vision - a cross-platform game engine that provides a powerful and versatile multi-platform runtime technology.
- Ogre3D - is a scene-oriented, real-time, flexible 3D rendering engine (as opposed to a game engine) written in C++.
- PlayCanvas - A WebGL Game Engine.
- Horde3D - small open source 3D rendering engine.
- Panda3D - a framework for 3D rendering and game development for Python and C++ programs.
- Godot - Open source game engine with rich API.
- Irrlicht - open source high performance realtime 3D engine written in C++.
- Three.js - Javascript 3D Library.
- Turbulenz - Turbulenz offers the ability to build, publish, iterate and monetise high-quality games that react like no others, with immersive 3D effects and real-time physics that open up a whole new world of unprecedented and extraordinary web content.
- Bullet - Real-time physics simulation.
- ODE - ODE is an open source, high performance library for simulating rigid body dynamics.
- Polycode - Open-Source Framework for creating games in C++ (with Lua bindings).
- Cinder - Cinder is a community-developed, free and open source library for professional-quality creative coding in C++.
Audio editors, sounds collections and more.
- Freesound - collaborative database of Creative Commons Licensed sounds.
- PacDV - royalty free sounds collection.
- Musopen - Royalty free music.
- Audacity - open source, cross-platform software for recording and editing sounds.
- Audiotool - Online music producer.
- Soundation - Online Professional music studio.
- Audiosauna - transforms your web browser into a fast and flexible music production studio with built in synthesizers and live effects.
- musagi - open source, fairly large and sophisticated music editor and synthesizer
- MadTracker - a powerful and efficient approach to making music. Versatility and compatibility are guaranteed due to full VST™, ASIO™ and ReWire™ support.
- MilkyTracker - open source, multi-platform music application for creating .MOD and .XM module files.
- FamiTracker - free windows tracker for producing music for the NES/Famicom-systems.
- Bfxr - A tool to make make sound effects for computer games.
- Game Engine Architecture
- Game Programming Gems
- The Art of Game Design
- Flow
- Rules of Play
- Theory of Fun
- The Visual Story
- CompoHub - A compilation site of many game jams in a timeline.