I like listening to RainyMood while I work to keep focused. The site isn’t that big, just 327kb, but its usability isn’t great and it’s full of tracking code. The site hits my adblocker(s) (plural at work per GPO) and so is slow to load.
With some “inspect element” I found the source files and made a tiny (just 35k) version that loops, is visually attractive, doesn’t track me, and loads instantly.