Godot is a powerful cross-platform game engine
Solar2D Game Engine main repository (ex Corona SDK)
UCI chess engine
Sandbox video game with a powerful physics engine
Open source voxel game engine with support for survival and crafting
Home theater software and entertainment hub for digital media
The game engine for everyone
scene-oriented, flexible 3D engine (C++, Python, C#, Java)
Open-source engine for Heroes of Might and Magic III
Urho3D Game engine
New Godot bindings for Swift
Godot Kotlin JVM Module
Embeddable unity game engine view for Flutter
Java/JavaFX/Kotlin Game Library (Engine)
KorGE Game Engine. Multiplatform Kotlin Game Engine & Korlibs
A cross-platform, open-source, pure C game engine for mobile game
Game engine supporting many 3D/2D formats and graphic effects
The AWS GameKit Plugin for Unreal
Chess engines that support the UCI or XBoard protocol.
Chess engines in APK format that provide the OEX format.
Engo is an open-source 2D game engine written in Go
3D Engine c++
Game engine to build text adventures.
Scripts and tools for Android.
GemRB is a portable open-source implementation of the Infinity Engine