Godot Engine - Feature-packed 2D and 3D open source game engine.
Firebase - Firebase is a cloud service designed to power real-time, collaborative applications for mobile and web.
Unreal Engine - Unreal Engine 4 is a suite of integrated tools for game developers to design and build games, simulations, and visualizations.
restdb.io - restdb.io lets you create databases and REST APIs quickly. Development databases are free. Powerful web-based and mobile-friendly data management.
BYOND - BYOND is the premier community for making and playing online multiplayer games.
RemoteStorage - An open protocol for per-user storage OWN YOUR DATA