Brain.fm - Music designed for the brain to enhance focus, relaxation, meditation, naps and sleep within 10 - 15 minutes of use.
Headspace - Meditation made simple. Brilliant things happen in calm minds.
MyNoise - Custom shaped online noise machines. Many Many generic sounds
Synctuition Meditation Program - Synctuition Meditation Program is a world’s most leading meditation app that comes with brand new 3D sounds that enhance the quality of sleep significantly.
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.
Calm - Calm.com can help you reduce stress and increase calm.