A Soft Murmur - Ambient sounds to wash away distraction.
Blanket - Improve focus and increase your productivity by listening to different sounds. Or allows you to fall asleep in a noisy environment.
Calm - Calm.com can help you reduce stress and increase calm.
MyNoise - Custom shaped online noise machines. Many Many generic sounds
Rainy Mood - Rainy Mood is the world's most popular rain simulator. Sleep, study, and relax with the sound of rain.
noice - Emoji Your Friends Can Hear (😃 + 🔊)