That's because I deleted a large majority of the Amoonguss discussion. It was running around in circles and no one was getting anywhere, the arguments that were being used for it to drop just weren't relevant at all. I've given my thoughts on Amoonguss and why I personally think it should stay A- so that's as much as I can do. If you want to continue talking about this then you should at least have better evidence to back it up than just calcs or saying it should drop solely on the fact that Pex/Growth exist. Calcs are good for supporting strong arguments but oftentimes people just don't know how to incorporate them properly, for example saying that Amoonguss can't switch into Ash Gren when any player shouldn't be allowing Gren to get a kill when they still have an Amoonguss to switch into it easily before Battle Bond.
Fair enough; you're the expert, and I didn't realize the discussion was mostly deleted. My bad.
So this isn't a useless post: I'd like to nominate
Charizard-Y A- -> A
Many teams have almost nothing to switch into Charizard Y. Its Fire Blasts are the most powerful Special Attack (bar stat boosts) in the tier due to Drought. Out of the A, A+, and S tiers, it one shots 14/20 pokemon with fire blast (counting dug, tho focus sash exists ofc), while it one shots 3 others with solar beam. Garchomp gets two shotted by fire blast or solar beam. The only reliable switch ins in these tiers are SubCoil zygarde and toxapex, and since zygarde has no reliable recovery it can't switch in over and over again either. In A-, it one shots every pokemon except itself, CharX, Heatran, MegaVenu, MegaSableye, and Fini. Fini it 2HKOs with Solar Beam (or even 1 solar beam and 1 fire blast), Venu and Sableye it 2HKOs with fire blast, heatran it can one shot with focus blast if no bulk, 2 shot otherwise, and char x is also 2 shotted with focus blast.
The point is that in this meta, the only good switch-ins Charizard Y has are chansey and toxapex (and nihilego if you're into that). It tears holes through any team it faces, pretty much, and has plenty of opportunities to come in, due to its typing (1 immunity, 2 4x resistances, a steel and fairy resistance, and others). In addition, all 3 primary mons that can switch into Charizard Y are prime targets for Dugtrio trapping, which means they make a great pair (add dug's electric immunity to that as well).
It hits ridiculously hard; 1HKOing the majority of the tier is nothing to scoff at, and 2HKOing most of the others is even better. What's not to like?
Well, there's a couple things. Stealth rock is a huge deal, especially with the most reliable defogger being fini, which is extremely predictable. And it also takes up the mega slot, which in this meta is also a big deal. However, it still has a hugely powerful attack, a decent speed tier and SpD to back it up, and a decent defensive typing (bar rocks). In terms of A-tier pokemon, I compare it to Volcarona. It's the wallbreaker to Volcarona's sweeper, trading out sweeping potential (though loltailwind could do work) for immediate and overwhelming power. However, both require rocks removal to hope to function (CharY at full health can take several notable attacks such as MMawile's sucker punch, lele's psychic, all of Greninja's attacks - bar Specs A-Gren's Hydro which it has a 63% chance of surviving -, and Gengar's shadow ball; CharY at half health can't take any of those), and both are walled by Chansey/Toxapex (+1 HP Ground admittedly has a good chance to 2HKO but haze exists and scald hurts).
I definitely think it's as good as stuff like Garchomp, Volcarona, M-Scizor, and Magearna. The only calcs I'll show are these:
252+ Atk Huge Power Mawile-Mega Play Rough vs. 252 HP / 252+ Def Shuckle: 108-127 (44.2 - 52%) -- 15.6% chance to 2HKO
252 SpA Charizard-Mega-Y Fire Blast vs. 252 HP / 252+ SpD Shuckle in Sun: 121-144 (49.5 - 59%) -- 99.6% chance to 2HKO
(Shuckle was made normal type for these calcs and was chosen for having the highest defense and special defense stats and for them being equal)
Its Fire Blast is more powerful than MMawile's Play Rough. Yes, it requires hazard removal, and yes, it takes up the mega slot, but that's a small price to pay for the sheer wallbreaking potential it has.