Sleep Cycle - Bio-alarm clock that wakes you up at optimal times based on your sleep patterns.
Rise: Track Sleep & Circadian - Wake up & fall asleep better
Sleep as Android - Common alarm clocks ignore your sleep cycles, they wake you on schedule no matter your are currently in your deep sleep. Waking up from deep sleep is unpleasant, it makes you tired and it may negatively affect your productivity during the whole day.
Beddit - A new kind of sleep tracker (No wearable sensors)
Pillow for iOS - An iOS companion that helps you sleep better 💤
Withings Sleep - A sleep tracking mat by Withings