I'll give my thoughts on some of the monsters of this metagame.
Zard Y has gotten a lot of hype, and for good reason. If you don't carry something like Latias, have fun sacking something to it every time it fires off an attack. 100 base speed is downright respectable, allowing Zard to outpace many things in the tier and deliver a powerful blow. I've just been running the standard three attacks and roost, since even "resists" are taking a beating. Here's some calcs to show how hard it hits a lot of pokemon in the tier.
252 SpA Charizard-Mega-Y Fire Blast vs. 0 HP / 4 SpD Keldeo: 170-201 (52.6 - 62.2%) -- guaranteed 2HKO
252 SpA Charizard-Mega-Y Fire Blast vs. 72 HP / 0 SpD Latias: 126-148 (39.4 - 46.3%) -- guaranteed 3HKO
252 SpA Charizard-Mega-Y Fire Blast vs. 0 HP / 0 SpD Latias: 126-148 (41.8 - 49.1%) -- 84.4% chance to 2HKO after Stealth Rock
252 SpA Charizard-Mega-Y Fire Blast vs. 0 HP / 0 SpD Dragonite: 156-185 (48.2 - 57.2%) -- guaranteed 2HKO after Stealth Rock
252 SpA Charizard-Mega-Y Fire Blast vs. 252 HP / 252+ SpD Mew: 226-267 (55.9 - 66%) -- guaranteed 2HKO after Stealth Rock and Leftovers recovery
252 SpA Charizard-Mega-Y Focus Blast vs. 252 HP / 252+ SpD Gigalith: 170-200 (45.4 - 53.4%) -- 91.8% chance to 2HKO after Stealth Rock and Leftovers recovery
As you can see, even "resists" are blown away by this thing lmao. Gigalith is boned if Zard hits focus blast enough (so never because it will just dodge haha).
Weavile is a bitch against fast teams, and even against bulky teams it's good thanks to knock off being so easy to spam. I run pursuit on this thing and pair it with anything that like Latias being gone, including Zard and Keldeo. Priority ice shard is nice, although not being able to revenge kill Dragonite sucks. Pursuit is nice considering the two best hazard removers in Stamie and Latias are weak to it, and in general it's still a busted move.
Speaking of Dragonite, this thing is so retarded. I've been running this thing on like 80% of my teams, and holy shit does it tear apart teams. Hazard removal is actually not ass, unlike late gen 6, with many great option like Starmie, Latias (dragon spam and healing wish are awesome), and even Mew or Scizor. If you do not pack an answer for this thing after a dd, you'll get your ass kicked a lot.
Speaking of Dragonite answers, good old Kyurem-B out speeds, ignores multi scale, and can revenge +1 Nite with scarf. What counters this thing? Lmao, what's a counter?
I'll share more sets later when I have more time. I've been having a lot of fun with this ladder.