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
Oh I remember first hearing the grapevine cover on the Avalanches Essential Mix, and that was also the first time I was surprised by a song being a cover also the fact that it comes after a song by Yoko Ono that sounds good makes this mix just extra special. The selection on this one is extraordinary