O3DE (Open 3D Engine)

Amazon licensed CryEngine from Crytek and launched the result in 2016 as Lumberyard: free, but tightly tied to AWS and Twitch. It found few users outside Amazon's own studios, and in 2021 it was renamed Open 3D Engine and given to the newly formed Open 3D Foundation under Apache 2.0 and MIT.

Much was replaced along the way: a new modular renderer, a system of "gems" for pulling in features, and its own component-based entity system. That makes O3DE one of the few engines with AAA ancestry and fully open source — far less widespread than Godot, but built for a very different budget.