Here are a variety of soothing background sounds to choose from:

IMAGE ATTRIBUTION: "Rain rain rain rain rain..." by GreyHobbit is licensed under CC BY-SA 2.0, "Eagle Creek Trip 17" by anoldent is licensed under CC BY-SA 2.0, "waterfall" by Kiwi Tom is licensed under CC BY 2.0, "Golden Bea "Oceans" by US Department of State is licensed under CC0 1.0, "Michiana forest" by kevin dooley is licensed under CC BY 2.0