Go 3D Game Engine
KotCity, an open source city simulator
Cinema Enters Game Console
3D C++ Game Engine - yet another open source game engine
ZED OS the clone of Windows XP
Modern 3D engine and IDE written using C# and C++.
Data-oriented and data-driven game engine written in Rust
Cross-platform 2D and 3D game engine
A cross-platform 2D game engine
Clojure in Unity
Character animation system for games and simulations.
Source code of the chapters of the book 3D Game Development with LWJGL
Blueshift is a cross-platform 3D game engine implemented in C++
Portable game engine with main focus on point-and-click adventures
Web powered cross-platform 3D, WebXR game engine
Children's learning programming language Karel the Robot in 3D
C/C++ , PHP, PYTHON, 3D ENGINES, CHROME NATIVE CLIENT
The Atomic Game Engine is a multi-platform 2D and 3D engine
Realtime 3D engine for game development
Bot for id Software's Wolfenstein 3D
online 4X browser game engine
Massively multiplayer online game server and client framework
Open-source, cross-platform, C++ game engine for creating 2D/3D games
A public domain cross platform 3D game