I use MyNoise.net, which I’ve raved about in the past, here, here, and here.
The guy who runs the site has been collecting and producing soundscapes for a decade or so. The slider controls for a particular soundscape allow you to add more of what you like and remove what you don’t. It’s brilliant through a good pair of noise-cancelling headphones.
Access is via browser or iOS app, so it may not work for you. As a way to avoid browser distractions, when I’m running MyNoise from my PC, I’ve dedicated a browser (fittingly enough, Opera) that I only use for MyNoise.net–with the URL to my favorite soundscapes preloaded on separate tabs.
Best,
Jim