SkinVision - App to detect skin cancer - with 70%+ accuracy
Suntimes - Android app (and widget collection) that displays sunlight and moonlight times for a given location.
SkinTheory - Control your acne. Scientifically.
SunIZup - SunIZup helps you to know the timings of the various Sunlight phases including the Golden Hour and...
Sunscreen Finder - Find the sunscreen that you will actually use
Natural Hour - A roman timekeeping add-on for Suntimes.