Godot Engine - Feature-packed 2D and 3D open source game engine.
Unreal Engine - Unreal Engine 4 is a suite of integrated tools for game developers to design and build games, simulations, and visualizations.
Adventure Game Studio - Adventure Game Studio provides the tools to make your own adventure, for free!
BYOND - BYOND is the premier community for making and playing online multiplayer games.
Cocos Creator - Cocos Creator is more than a efficient, lightweight, free, open-source, cross-platform graphics engine: it's also a platform to create 3D content in real time.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.