Skymin, Charizard-Y
I think people are overlooking char-y here, remember how char-y + venusaur was scary as fuck once upon a time, when stratos Sun came out. The raw power of it's sun boosted heat-waves forces you run a sturdy sun check on every team and made wide guard spams popular, initially people used scarf landos for rock slides but as the meta grew and people realised they didn't need as much investment so they started investing into bulk which again gave birth to AV lando as a psuedo sun check. I mean drought is an incredible ability on a 159 special attack pokemon and even with heatrans everywhere, till the end of ORAS charizard-y consistently remained a large threat. Just something to consider.
And skymin is just well Skymin...