Sleep Cycle - Bio-alarm clock that wakes you up at optimal times based on your sleep patterns.
Sleepty - Sleepty is alarm clock based on sleep cycles. It will help you to wake up in your light sleep cycle.
Sleep Time - Alarm Clock - Sleep Time provides insight into your sleep patterns. By tracking your level of movement throughout the night, Sleep Time generates customized sleep data in easy-to-read charts.
Alarm Klock - A better alarm clock.
Sleep Calculator - Want to wake up in a good shape?
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.