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.
Moodwill - Create and listen for free to your perfect nature sounds environment with music to help you concentrate, relax, sleep and overall feel better.
Defonic - Create a unique sound environment at home or in the office
zenmix.io - Ambient background sound generator
Noizio - Feeling that the noise of the big city is too much for you to bear?
A Soft Murmur - Ambient sounds to wash away distraction.