I would never suggest ranking regular Pokemon moves because there's so many of them and there's a lot of them that are either shit or rather obscure (that many people probably haven't heard of). The sheer number of regular Pokemon moves makes it completely impossible to run a ranking project for that.
Z-Moves are much different than regular Pokemon moves because Z-Moves put a huge amount of focus into really flashy looking animations. There's also far less Z-Moves than regular Pokemon moves, so it's much easier ranking Z-Moves. I already pointed out there are 29 Z-Moves currently, not counting the Z-Move versions of status moves.