Godot Engine - Feature-packed 2D and 3D open source game engine.
Ninja Kiwi - Ninja Kiwi, creators of awesome free online games.
GDevelop - GDevelop is an open-source game making software designed to be used by everyone.
Play iDev Games - Play by iDev is the next generation of gaming on the internet.
Unreal Engine - Unreal Engine 4 is a suite of integrated tools for game developers to design and build games, simulations, and visualizations.
Snesfun - Retro Nintendo games