A graphics engine + toolkit.
Open source network game service
Sprite Font Creator
Create your own animated characters for games with ease!
3D world editor for game development
A tool for editing OHRRPGCE RPG files
Convert Ren'Py visual novels into a format your ebook-reader knows
Allows the Sourcemod FunCommands to be limited
A very small multi-platform game engine for creating desktop games.
An open source skateboard games engine written in C# and .NET.
Little game background framework in java.
Simple and scalable 3d javascript game engine
3D Web UI, Embed Web and Flash in 3D Games, based on WebKit
Pear3DEngine is a modern and modular 3D development framework
An extensible development framework for roleplay games.
Phobos editor is a generic resource editing system.
An open source C++ console based game (Windows only).
Open Source Virtual World and MMOG Development Platform
War commandos - Universal Soldier