Headspace - Meditation made simple. Brilliant things happen in calm minds.
Meludia - Listening exercises and to sharpen your ear and music theory skills
Calm - Calm.com can help you reduce stress and increase calm.
GNU Solfege - GNU Solfege is free music education software.
Medito - 100% Free Meditation App that will improve your Mental wellbeing with the help of Guided Meditations, Breathing Exercises, Mindfulness Practices, Relaxing Sounds, and more.
Perfect Ear - A simple yet advanced application for improving your solfege skills.