Firebase - Firebase is a cloud service designed to power real-time, collaborative applications for mobile and web.
Unity - The multiplatform game creation tools for everyone.
restdb.io - restdb.io lets you create databases and REST APIs quickly. Development databases are free. Powerful web-based and mobile-friendly data management.
Godot Engine - Feature-packed 2D and 3D open source game engine.
RemoteStorage - An open protocol for per-user storage OWN YOUR DATA
Blender - Blender is the open source, cross platform suite of tools for 3D creation.