Any examples of web apps using sound effects?

What kind of sound effects? I generally don't turn on effects when I use software. Unless it's a music program.

Small things like sound feedback when clicking a button, submitting a form, content loaded, etc.

Got it. No examples. Maybe check this out: snd.dev

SND: Crafted UI sound assets for UX developers

UI sound assets, developed in collaboration with multiple sound designers, are designed to fit the components used in many modern UIs.

snd.dev