In my opinion, Rihanna’s “Stay” is one of her better songs to be released. It looks like I’m not alone with this notion because we have a total of 11 Youtube videos of artists who chose to cover the tune. That being said, the majority chose to go the same route as the original, sticking to a simple piano backdrop or even the same instrumental. But there are a couple unique gems in there that I think you’ll enjoy.
Amanda Lee x Phil Good x Vegasky Labs
Anthony Lee x Lawrence Devera
a-Tunes 
What about Rocky Sandoval cover?
We got that one already! https://a-tunes.net/2013/03/05/the-bruno-mars-rihanna-youtube-covers-round-up-3513/