I–V–vi–iii–IV–I–IV–V in G
GDEmBmCGCD
I–V–vi–iii–IV–I–IV–V · G major · Canon
Play it in the builder →How it works
Pachelbel's eight bars, all diatonic, the bass falling in steps and thirds. Loop it and it never wears out, which is why half of pop has borrowed it since.