Taskful - Deadlines, meet your match.
Sleep Cycle - Bio-alarm clock that wakes you up at optimal times based on your sleep patterns.
Calendarist - Time blocking companion for Google Calendar
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.
Gone - An ephemeral to-do list
Talalarmo - Minimalistic android alarm