There's a great selection of free ambient sounds on Moodist. This online sound generator offers 54 types of sounds that automatically generate when you select one and click play.
You can choose from rain, animals, city, transportation, and many other categories of sounds. I love how easy to use this website is.
These sounds have been helping me focus during work and to unwind before bed lately. You can also mix various sounds together, adding as many or as little as you want. My personal favorite is the rain and wind chimes together.
