Sleep Cycle - Bio-alarm clock that wakes you up at optimal times based on your sleep patterns.

Oneiro Note - An easy way to track and analyse your dreams

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.

Sleep Better - Track sleep cycles, monitor dreams & improve bedtime habits

Talalarmo - Minimalistic android alarm

Rise: Track Sleep & Circadian - Wake up & fall asleep better