A game engine with an emphasis on real-time cutting-edge solutions
Zig game engine & graphics toolkit
Game engine supporting many 3D/2D formats and graphic effects
A game engine powered by python and panda3d
GemRB is a portable open-source implementation of the Infinity Engine
Real Time Strategy game engine supporting early Westwood classics
Descent 3 by Outrage Entertainment
A dead simple 2D game engine for Go
3D game engine/framework in C, with Luajit and Python bindings now
Godot Minimal Theme
2D JavaScript Physics Engine
JavaScript-based game engine designed to empower developers
High performance UI layout library in C
Orx: Data-Driven Game Engine
A modern, cross-platform Quake game engine based on FitzQuake.
SDL based generic 2D game engine
A 2D rigid body physics engine for the web
C++ lightweight cross-platform game engine
Old-school 2D game engine
Full featured MUD server with all the trimmings.
The multiplayer game engine