Gaming meets modern C++ - a fast and reliable entity component system (ECS) and much more

Cross-Platform C++ 2D/3D game engine

Piccolo (formerly Pilot) – mini game engine for games104

A Vulkan game engine with a focus on data oriented design

Easy to integrate Vulkan memory allocation library

Filament is a real-time physically based rendering engine for Android, iOS, Windows, Linux, macOS, and WebGL2

Lightweight and modular C++11 graphics middleware for games and data visualization

A modern cross-platform low-level graphics library and rendering framework

C++ cross-platform 3D graphics SDK. Includes demos & helper code (resource loading etc.) to speed up development of Vulkan, OpenGL ES 2.0 & 3.x applications

Stride (formerly Xenko), a free and open-source cross-platform C# game engine.

Powerful, mature open-source cross-platform game engine for Python and C++, developed by Disney and CMU

Cross-platform, graphics API agnostic, "Bring Your Own Engine/Framework" style rendering library.