Here are a few to get things started:
Don Henley’s The Boys of Summer as an 80s synth tune
Bossa nova version of Crowded House’s Don’t Dream It’s Over
Reggae-ish version of Aretha Franklin’s Respect
A capella men’s ensemble version of Lady Gaga’s Bad Romance
That is my favorite version of Thunderstruck, even more than the original.
(There was a really cool article I read ages ago that discussed how similar metal and classical music structures are. Have no idea where I found it.)