Godot Engine - Feature-packed 2D and 3D open source game engine.
Apache Cordova - Platform for building native mobile applications using HTML, CSS and JavaScript
Unreal Engine - Unreal Engine 4 is a suite of integrated tools for game developers to design and build games, simulations, and visualizations.
React Native - A framework for building native apps with React
BYOND - BYOND is the premier community for making and playing online multiplayer games.
PhoneGap - Easily create apps using the web technologies you know and love: HTML, CSS, and JavaScript.