I'm building https://ambiph.one, an ambient music/white noise/soundscape web app. It's a free alternative to apps which have a monthly fee or are covered in ads. Lots of lovely feedback from people who've found it useful for sleep, tinnitus, focus, ADHD etc

Just launched a PWA and now working on more mixing features like spatial audio, reverb and high/low-pass filters to let you create even more immersive sound environments.