OGRE
The Object-Oriented Graphics Rendering Engine is a modular C++ 3D renderer with scenes, materials, animation, and plugins.
Why use it
Teams avoiding a full game engine get a long-lived rendering base while retaining gameplay architecture control.
Where it fits
Find engines, frameworks, code libraries, version control, and production automation.
What to check
Physics, audio, networking, and an integrated editor are outside its core and require other middleware.