Castle Game Engine - An open-source 3D/2D game engine for ObjectPascal.
LinkedIn Learning - Online training through LinkedIn's professional network.
Open 3D Engine - Open 3D Engine is an open-source 3D game development engine in real-time.
Fluany - Everything you need to force your mind to learn
Godot Engine - Feature-packed 2D and 3D open source game engine.
Hackr.io - There are tons of online programming courses and tutorials, but it's never easy to find the best one. Try Hackr.io to find the best online courses submitted & voted by the programming community.