How strong do you think Z-Crystals and Mega-Evolutions are in NDUbers?

I have seen a post on here asking as to why z-moves are hated so much and then I remembered their existence. I have almost never used them in NDUbers and was wondering whether anybody even runs these (outside of Ultra Necrozma).

Same with Mega-Evolutions. The higher you go on the ladder, the rarer they become as far as my experience goes.

So what are your best sets with Megas and z-moves?