Sleepy Baby - Help your baby sleep with the Sleepy Baby soundboard.
Plum Village - Free mindfulness app w/ Zen Buddhist meditations + teachings
Power Nap App - Best napping timer with relaxing sleep sounds
Calm - Calm.com can help you reduce stress and increase calm.
MyNoise - Custom shaped online noise machines. Many Many generic sounds
Headspace - Meditation made simple. Brilliant things happen in calm minds.