myNoise

myNoise is an enormous library of soundscape generators, and it rewards exploring. Each generator lets you adjust frequency bands with sliders, so you can tune a rainforest, a sci-fi spaceship or a thunderstorm to your own taste, rather than settling for a fixed loop. People use it for focus, for sleep, and for relief from tinnitus, according to the site's description. There is enough variety to browse for days: when you arrive, you will see categories and a long list of generators, and each has a different personality. It can feel overwhelming at first, so pick one that matches your mood and play with the sliders to see what changes. If you are the type who likes to fiddle until a sound is just right, this is a very good place to lose an afternoon, and a useful tool once you find your favorite.