I'll make a list on what I've seen on the ladder, what I've used myself and what I think is viable/useful
S rank
- View attachment 37924 I've only seen Keldeo with ground, mainly because Keldo doesn't see a lot of usage in Hidden type. But Ground is nice and all, though it's Quad weak to Grass Knot. It checks Thundurus which is nice
- View attachment 37925 Metagross uses mainly Flying and Dark, as they directly benefit him instead of adding Stab coverage moves. Dark for Stab Pursuit and Neutral to Dark and ghost, while flying means you're immune to Ground and can nicely check Dragonite if it lacks Fire punch
- View attachment 37926 I guess Sableye runs Steel and Poison, I haven't seen a lot of discussion about him on the forum which would be nice. I've only seen Steel and Poison since they give him a handful of resistances
I haven't seen Metagross more than once (And it wasn't even Mega Metagross), so I don't have a lot of concrete worth to add -I will note that Fighting is another option, between the Dark resistance, additional Stealth Rock resistance, and Hammer Arm STAB letting Metagross hit things pretty hard. Loses the Fairy resistance, which is unfortunate, but being neutral to Flying is not usually a big deal while Fighting being weak to Psychic is completely trivial due to the innate double resistance.
I haven't seen Mega Sableye much myself either, but it really struggles against too many of the really amazing Pokemon no matter what typing you give it -it can't really do anything about Unaware Clefable, even Will O Wisp won't help it against Fire Mega Altaria, Grass Manaphy will probably just murder it with Tail Glow Scald... the list goes on, and the fact that both its most obvious adds are vulnerable to Ground makes it predictable.
A rank
I'll add more if I have time
- View attachment 37927 Azumarill runs steel, fighting or dark from what I've seen. Steel gives it more resistances, mainly to steel, poison and grass. Fighting and Dark is mostly for Stab Coverage, Superpower and Knock off
- View attachment 37928 S rank IMO, Altaria runs Fire and Steel. They're both equally good and it all depends on your playstyle. If you're running more offensively you can run Fire giving it Stab Fire blast and Will O Wisp immunity. Steel is also nice as it gives it a stealth rock resist and more resistances I think.
- View attachment 37929 Bisharp runs mainly ground and ghost, which makes Bisharp a serious threat in this metagame as there's is really no way to know what it's running. Be very careful when facing Bisharp, as locking yourself into a fighting or ground move can mean it's gg
- View attachment 37930 There has been some discussion about this on the forums, it mainly runs Dark and Ground for stab earthquake and stab Crunch. But since the metagame is so full of Ground moves it's not A+ Material as it is in OU
- View attachment 37932 Clefable is deadly and unpredictable. It runs Steel and Fire typing, MG runs fire for Stab Fire blast while Unaware run steel to check a ton of the set up sweepers. Definitely good in this metagame.
- View attachment 37933 Gengar is great in this metagame. It has no weakness with Ghost, Dark and Poison. It's incredible deadly with unresisted coverage(I think?) and a huge move pool. I'd just advice everyone to run Dark on it, as it's so amazing. S rank imo
- View attachment 37936 Steel, fire and flying is what I've seen. Ground could also be nice but I haven't seen it in action.
I've also seen Dragon Azumarill, which provides a nifty set of resistances so long as you don't encounter a Freeze Dry Pokemon. (So basically Mamoswine) Azumarill probably deserves an A rank just because it's a rare example of a Pokemon that has something more than 1-2 highly viable adds -Fire is also very good on it and provides it Will O Wisp immunity. It was very popular in XY Hidden Type and I'm surprised I haven't seen people running it to check Mega Altaria -if Mega Altaria is carrying Fire Blast over Earthquake (Or Roost over a third attacking move, which I've seen) it's not got a lot it can do about Azumarill.
Jack Dalton also thinks S rank is appropriate for Mega Altaria. I don't really agree, in part because both its best adds are vulnerable to Ground and there are a number of Pokemon it doesn't have much of an answer to, such as Flying Heatran, making it a lot easier than, say, Steel Dragonite to check or counter, but A+ seems appropriate to me.
I assume you mean Flying or Ghost for Bisharp. Bisharp is good, though a lot of the things it normally murders outright are carrying typings it can't take out so easily, and ultimately I think the main thing it has over (Mega) Tyranitar is Sucker Punch, which is nothing to laugh at but Mega Tyranitar can sweep teams after a Dragon Dance or two -Bisharp still has to fear fast statusers and the like after a Swords Dance/2 Swords Dance/Defiant triggers/whatever. Defog is also oddly unpopular in Hidden Type in my experience (Making Defiant less valuable, though I've no idea why, so I'm not willing to assume that will stay true. Sticky Web is also less popular, for obvious reasons: it's not unusual for a team to be 4 non-grounded Pokemon, limiting the value. (Which is also a flaw with Flying Bisharp -no Sticky Web Defiant boost for you)
I've covered Mega Charizard X in previous posts. Somewhere in A sounds basically right to me.
Actually, Clefable often runs Water or, for reasons that mystify me, Dragon. It's been a while since I've fought a Steel Clefable, now that I think about it... a solid, important Pokemon, at any rate.
Yeah Gengar running Shadow Ball+Focus Blast is only resisted-or-better by Normal/Ghosts, and with Dark Pulse not even those. (And then Ghost Mega Lopunny comes along and laughs at you) I usually fight Electric variants myself, though I've seen the odd Steel type, I guess fishing for more resistances to keep Gengar in the fight longer. Regardless, it's not a given what it will be doing and weaker Knock Offs and Sucker Punches will often fail to KO Dark Gengar, which can turn the tide of a match. Maybe A- minus, because it's still hard to keep Gengar alive, and attempting to do so tends to create movepool problems.
I think I've seen (Mega) Diancie like once. The only thing I really have to add is that it still struggles due to its movepool problems -no Physical Fairy move and no Special Rock move, barring Hidden Power Rock which means not adding a type. I doubt it's an A, honestly.