I was thinking about a set for Meloetta using Relic Song (as the sleep chance with Serene Grace, plus power and accuracy is quite good) and would stats change? Or not?
The user sings an ancient song and attacks by appealing to the hearts of those listening. It may also induce sleep. Relic Song page
So no, Relic Song does not change your stats. It does have a Sleep chance though. Please don't ask questions you can easily find yourself on the site.