FlatRedBall - Cross-platofrm 2D game engine using C#, focused on developer productivity, transparency, scalability, and ease of use.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
MonoGame - MonoGame is an open source implementation of the Microsoft XNA 4 Framework.
Autodesk 3DS Max - 3ds Max is software for 3D modeling, animation, rendering, and visualization. Create stunning game enrivonments, design visualizations, and virtual reality experiences.
Godot Engine - Feature-packed 2D and 3D open source game engine.
ZBrush - ZBrush is a digital sculpting and painting software solution.