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.

T-Clock Redux - T-Clock Redux in an enhanced fork of Stoic Joker's T-Clock 2010 with ISO week number support...

Sleepedy - Personal sleep coaching & therapy

ClocX - ClocX - freeware analog clock for Windows desktop with many features like calendar, alarms, skins, antialiasing and transparency.

Pzizz - Sleep at the push of a button! Now with "Focus"

DS Clock - Keep your time synchronized with Atomic Time servers, using customizable digital desktop clock with westminster chimes.