MathCrunch - Learn math stress free
Unity - The multiplatform game creation tools for everyone.
Kalam Labs - Twitch for Science
Godot Engine - Feature-packed 2D and 3D open source game engine.
Code Fight Club - A fight club you can talk about. Less punching, more coding.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.