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.
Moodly - Get a better sense of focus and relaxation by listening to ambient nature sounds.
Noizio - Feeling that the noise of the big city is too much for you to bear?
Focus - New Tab page that gives you a moment of calm and inspires you to be more productive.
Hocus Focus - A Mac menu bar utility that hides your inactive windows
Hipster Sound - Be productive at home with the sounds of busy cafes.