So I was involved in a bunch of YK covers, from my solo channel(KikyoCovers), Nostra Harmonia (Previously CantaPerMeCovers), and a duet group (Soleil). Here's a few:
Solo:
Lirica
Kimi no Gin no Niwa
Sprinter
One Light
Duet:
Magia
Nostra Harmonia:
Mune no Yukue
Seiya
Red Moon
All but Red Moon...
CantaPerMeCovers
Thread
fictionjunction
kajiura
kalafina
kimi no gin no niwa
lirica
magia
one light
redmoon
seiya
sprinter