Godot Engine - Feature-packed 2D and 3D open source game engine.
MonoGame - MonoGame is an open source implementation of the Microsoft XNA 4 Framework.
GDevelop - GDevelop is an open-source game making software designed to be used by everyone.
RPG Maker - Make your own PC game with RPG Maker. Our easy to use tools are simple enough for a child, and powerful enough for a developer. Try it free today!
ct.js - ct.js is a 2D game editor (desktop app) based on web technologies.
Adventure Game Studio - Adventure Game Studio provides the tools to make your own adventure, for free!