Unity - The multiplatform game creation tools for everyone.
Noisli - Noisli is a fantastic background noise and color generator for working and relaxing. Online soothing ambient sounds like White noise, Rain and Coffee Shop.
Godot Engine - Feature-packed 2D and 3D open source game engine.
Noizio - Feeling that the noise of the big city is too much for you to bear?
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
zenmix.io - Ambient background sound generator