fheroes2 is a recreation of Heroes of Might and Magic II game engine
Cocos simplifies game creation and distribution with Cocos Creator
A high-performance, industry-standard 2D physics engine built on Box2D
Open-source engine for Heroes of Might and Magic III
A modular Common Lisp game engine
High performance UI layout library in C
3D and 2D game engine written in Rust
Multi-platform Engine for Desktop, XBOX (UWP) and Mobile games
LayaAir is an open-source 2D/3D engine
A game engine with an emphasis on real-time cutting-edge solutions
A completely free, open-source, 2D game engine
Eva.js is a front-end game engine for creating interactive projects
Open 3D Engine (O3DE) is an Apache 2.0-licensed multi-platform 3D
The Tiny JavaScript Game Engine That Can!
Open source library for creative expression on the web, desktop, etc.
Zig game engine & graphics toolkit
GemRB is a portable open-source implementation of the Infinity Engine
A Complete WebGPU Game Engine for Browser & Desktop Arcade Oriented
SDL based generic 2D game engine
Animation Compression Library
Game framework with AI
The multiplayer game engine
Modified source engine (2017) developed by valve and leaked in 2020
A high speed C++17 Vulkan game engine
DOOM / Heretic / Hexen source port with enhanced graphics and UI