I'll have to look some of these up. I've been enjoying Lindsey Stirling, most recently her rendition of Radioactive with Pentatonix.
I'll have to check that out. Within Temptation has also done a cover of "Radioactive", but I haven't listened to it yet.
I like Lindsey Stirling's "Mission Impossible" with The Piano Guys, and her "Phantom" medley.