Xamarin - Create iOS, Android and Mac apps in C#
Unity - The multiplatform game creation tools for everyone.
Kony - Kony is a mobile application application development platform that facilitates companies to deliver innovative mobile solutions.
Godot Engine - Feature-packed 2D and 3D open source game engine.
Monaca - Monaca makes the hybrid mobile app development process with PhoneGap/Cordova simpler and...
Blender - Blender is the open source, cross platform suite of tools for 3D creation.