CRYENGINE is a powerful real-time game development platform created by Crytek.

3D C++ Game Engine - yet another open source game engine

Improved version of the X-Ray Engine, the game engine used in the world-famous S.T.A.L.K.E.R. game series by GSC Game World.

Go 3D Game Engine

A game engine powered by python and panda3d.

Cross-platform (desktop, mobile, console) 3D and 2D game engine supporting many asset formats (glTF, X3D, Spine...) and using modern Object Pascal

A C99 3D game engine

A 3D game engine for the Web

Realtime 3D Game-Engine with a focus on space sim. Written in C++ 14

2 Kilobyte 3D racing game in JavaScript

A basic cross-platform 3D game engine

G3N Game Engine Demo

An easy to use, Open-Source, 3D game engine for iOS/macOS game development.

Cross-platform game engine.

An open source, cross-platform game engine designed for indie developers.

The Dæmon game engine. With some bits of ioq3 and XreaL.

Open Source Editor and API for creating games in Flax Engine

[abandoned] C99 cross-platform 3D game engine with absolute minimum of external dependencies

Java 3D Physics Engine & Library

Modern OpenGL renderer written in C++17

Fusee aims at becoming a multiplatform 3D realtime engine with a strong emphasis on content transformation and manipulation. Fusee is written mainly in C# and can be programmed in C#. Fusee builds bridges to make your code run in environments that don't support C#, like Content-Creation-Software, C++, Plug-In-APIs and native HTML5/WebGL Javascript code.

Mage is a 3D Game Engine, built on top of THREE.js. It features Unity-like scripting, AMMO.js powered physics workers, an Infernojs powered UI and a clean API. Under (very) active development.

libGDT - The C++ Game Developement Templates Library

2D and 3D game engine based on OpenGL OpenGL ES and Vulkan

3D OpenGL engine for Go

A free C++ game development framework for Windows.

Port of PyODE for Python 3