Or a privacy respecting way on the web.
I am a big fan of MyNoise, which mixes real-life recorded sounds, but you have a ridiculous amount of control over almost everything.
It’s browser-based, so compatible with any device. Once it has downloaded the sounds, it doesn’t use any more bandwidth.
Definitely worth supporting with a donation.
The amazing thing is that one guy is behind everything you see and hear. Dr Pigeon is like a polymath. He develops and runs the site, creates all the sounds and plays all the instruments (with a few exceptions). I beg everyone who uses that site to donate, so he can keep going.
Using Freetube (a youtube privacy frontend) you can listen to white noise.
What exactly are you looking for? Why not just download one of those 24+ hours white noise videos from YouTube and play those with a media player?
I’m looking for something like Dark Noise on iOS, which allows you to mix different sounds and regulate their volumes.