Godot Engine - Feature-packed 2D and 3D open source game engine.
Android Studio - Android development environment based on IntelliJ IDEA
Flutter.dev - Build beautiful native apps in record time 🚀
MonoGame - MonoGame is an open source implementation of the Microsoft XNA 4 Framework.
ASP.NET Core - With ASP.
ct.js - ct.js is a 2D game editor (desktop app) based on web technologies.