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.
Defonic - Create a unique sound environment at home or in the office
Brain.fm - Music designed for the brain to enhance focus, relaxation, meditation, naps and sleep within 10 - 15 minutes of use.
Noizio - Feeling that the noise of the big city is too much for you to bear?
Supercreative Profiles - Collaborate with super freelance designers.
Noizer - Ambient sounds like Noisli, but free