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.
Sounds of Earth - Listen to relaxing ambient sounds of nature
Earth.fm - Earth.fm is a non-profit, growing library of pure, high quality nature sounds from around the world.
Serene - The macOS app to get your focus back
White Noise - White Noise to help you sleep and games to wake you up.
Fan of Sleep - White noise generator to help you fall asleep