Cross-platform 2D and 3D game engine with modular architecture
Open 3D Engine (O3DE) is an Apache 2.0-licensed multi-platform 3D
Amazon Lumberyard is a free AAA game engine
A fast, scalable, distributed game server engine/framework for C++
Blueshift is a cross-platform 3D game engine implemented in C++
Intrinsic is a Vulkan based cross-platform game and rendering engine
Open-source, cross-platform, C++ game engine for creating 2D/3D games