Headspace - Meditation made simple. Brilliant things happen in calm minds.
Bond - A simple app that reminds you to keep in touch with people
Plum Village - Free mindfulness app w/ Zen Buddhist meditations + teachings
Thankster - Automagically send hand written cards
Calm - Calm.com can help you reduce stress and increase calm.
pplQ - A daily nudge to keep in touch with someone important to you