iOS 26: Use Background Sounds to help with sleep, focus, and more (support.apple.com)

Sounds list: {Balanced, Bright, Dark} Noise, Ocean, Rain, Stream, Night, Fire, Babble, Steam, Airplane, Boat, Bus, Train, Rain On Roof, Quiet Night.

They're pretty high quality!

Many of these exist and can be used on iOS 18, as well - for those of you not willing to embrace Liquid Eyesore