This app was mentioned in 2 comments, with an average of 2.00 upvotes
Then get the free to try one.
Here are some that came up recommended on reddit at some point but I'm sure there are more.
Mynoise & /r/MyNoise
asoftmurmur web by /u/gabemart
Sleepio by /u/nomadprogrammer
Or you can check you /r/asmr for all kind of sounds supposed to trigger autonomous sensory meridian response. Some people find it relaxing.
This is fun is a different way : http://youarelistening.to/m/chicago
There are a lot of noise apps for android though. I'd recommend this one https://play.google.com/store/apps/details?id=anti.rain