PowerNap

PowerNap is a very powerful, yet intuitive Nap Timer application that focuses on ease-of-use and powerful functionality. Setting a nap duration is as easy as moving a slider. Once the alarm has been set, PowerNap will display an interactive notification to allow you to view the remaining minutes of the nap, add or subtract additional minutes to the duration, and even cancel the alarm. PowerNap is also very customizable and following options are adjustable:

-default nap duration

-default snooze duration

-default adjustment increments

-alarm ringtone

-sound only

-vibrate only

-turn on 'do not disturb' while napping (Marshmallow and above only)

The vibration feature even includes a randomizing algorithm that prevents the user from "getting used" to the vibration pattern and not waking up. If you're an avid nap taker, this is for you!