Sleep Cycle - Bio-alarm clock that wakes you up at optimal times based on your sleep patterns.
SleepBot - SleepBot is a sleep tracking app available in Google Play and the Apple App Store.
Talalarmo - Minimalistic android alarm
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.
Gentle Alarm - Gentle Alarm can consider your sleepcycles to wake you up when you are in light sleep.
Sleep Better - Track sleep cycles, monitor dreams & improve bedtime habits