Practice.dev - Practice programming for free
Castle Game Engine - An open-source 3D/2D game engine for ObjectPascal.
TeachYourselfToCode - Learn to code with tutorials recommended by programmers
Open 3D Engine - Open 3D Engine is an open-source 3D game development engine in real-time.
Tynker - Game Worlds for Kids to Learn Programming
Godot Engine - Feature-packed 2D and 3D open source game engine.