Advanced Sleep Timer
Advanced Sleep Timer is an all new kind of sleep timer that will silence your music naturally. Other sleep timers work by setting a timer, and then silencing the music when the timer ends. Advanced Sleep Timer works by monitoring your music and then silencing it after a certain number of songs have played. For example, set the app to count for 3 songs and after 3 songs have played your music will be silenced.
Check out the FAQ page here.
Check out the app changelog here.