It’s obvious that Rihanna covered “Tainted Love” by Soft Cell with “SOS”. But did you know that Crazy Town’s Butterfly” samples “Pretty Little Ditty” by Red Hot Chili Peppers? Or that Lady Gaga’s “Pokerface” used music from Boney M.?
There’s a whole database about sample-based music called WhoSampled. Try browsing it. It’s astonishing.