UCI chess engine
UZDoom is a feature centric port for all Doom engine games
3D Engine c++
A Minecraft mod designed to improve frame rates
Game engine supporting many 3D/2D formats and graphic effects
GemRB is a portable open-source implementation of the Infinity Engine
An open source flight dynamics & control software library
A .NET ascii/ansi console engine written in C# for MonoGame and XNA
Go bindings for raylib, a simple and easy-to-use library
A modern, cross-platform Quake game engine based on FitzQuake.
Orx: Data-Driven Game Engine
A free transportation simulator game
0 A.D. is a free, open-source, cross-platform real-time strategy game.
Chess engine written in Pascal with an UCI interface.
Arianne is an engine to develop multiplayer online games like Stendhal
GLScene Engine for Delphi & C++Builder VCL Windows 32/64
Chess Database and PGN viewer
One-click account switcher for Steam, Riot, Battle.net and Epic
Europa Universalis 4 save game editor
Colonize the New World.
GEDKeeper - opensource and crossplatform genealogy management program