Solarus Action-RPG game engine - Solarus is a free and open-source Action-RPG game engine.
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!
Godot Engine - Feature-packed 2D and 3D open source game engine.
EasyRPG - RPG Maker 2000 and RPG Maker 2003 compatible replacement.
RPG Paper Maker - Website
RPG Playground - Make your own Role Playing Games, fast and easy.