I Want Sleep! is a no-frills sleep sounds with over 100 sounds to choose from in its library. Choose your favorite, set the sleep timer, and get some rest.
I always have trouble falling asleep on my own. This app has been a lifesaver. Simple to use and lots of choices. Yes, it has the standard rain sounds and white noise, but also city sounds and some other atypical choices for when you are sick of the nature sounds. Highly recommend.