My Suggestion
Clefable to S -Clefable can be problem in many ways it can some times Set stealth rock or act as wish passer or even sweep with Calm Mind or stall with Cosmic Power
Magnezone to -A Magnezone is great pokemon as it has become famous with Drag Mag Core and also mega pinsir + Magnezone + Landerous Therein offense Core. it can also trap Steel Pokémon because of its ability.
Talonflame to A I think Talonflame is being Overrated just because of its ability and Stab Moves It has Bad Stats But even though it has nice Ability and Stab Moves it does not deserves A+
Scolipede to -B Since it is part of Baton pass users after its Ban probably less people will be using it even without Baton pass team it can serve great as Life Orb attacker And before Getting it can Baton pass the speed to any other pokemon it can be usefull but it does not deserves B
Volcarona to +C Volcarona is very Good bulky Specail attacker it can abuse its Bulk with its move Quiver Dance it can easily Sweep it can sometimes use Rain Team
Kyurem-Black to +B Kyurem black is not Good as it has many weakness and it does have Decent Speed with is 95 and it is good but due to so many weakness it cant be at A-
Alakazam to -A Alakazam mega is very good it is having 175 special attack with is so much enough to kill a pokemon and speed of 150 stats it can easily Sweep with its Power but unfortunately it has very weak Physical defence still it is very fast it can kill before you even move
Edit Sorry I forgot
I'd like to focus on Kyurem-B specifically; I'd talk about Talonflame too, but it's been discussed already as to why it should stay A+. I've only used Kyurem-B a little bit, but B+ is just too low for it.
Tyranitar has many weaknesses too; that didn't stop it from being S-rank in BW. Or, for a better comparison, Keldeo has the same number of weaknesses as Kyurem-B (5) and it's still S-rank. Having "many weakness" (nice grammar, dude) does not stop a Pokemon from being good.
Kyurem-B is one of the few effective wallbreakers that does not use up a Mega slot, so if you wanna bring up "But Mega Heracross is a better wallbreaker," that won't fly. Yes, Mega Heracross gets the job done better, but it also
uses your Mega slot. What if you wanna run Mega Manectric instead? Or maybe you wanna use Mega Scizor, Mega Tyranitar, Mega Aerodactyl, Mega Alakazam, or whatever else.
Kyurem-B's sky-high 170 base Attack stat is the highest of any non-Uber, non-Mega Pokemon, and to put that into perspective: That means it has 376 Attack
uninvested. With an Attack stat needing minimal investment, you can afford to invest in Special Attack, making you hit hard no matter what side of the spectrum you're hitting on. But other than that, it can run a specially-biased Mixed set or a physically-biased Mixed set. Need Physical walls weakened more? Run the specially-biased one. Need Special walls weakened more? Run the physically-biased one. You can also run so many more sets, Substitute for example. All of these sets are highly effective, just being able to punch holes in your opponent's walls, and Teravolt is pretty nice too; the most obvious example I can give is that it allows Kyurem-B to hit Rotom-W with Earth Power, landing a solid 2HKO without needing to use Outrage (physically-biased needs Stealth Rock.) In addition, it ignores Thick Fat, so Mega Venusaur isn't taking an Ice Beam well at all.
Also, having two different main wallbreaking sets adds a certain degree of versatility to Kyurem-B, even though it has a shallow movepool. Slowbro stops the specially-biased set easily, but, after Stealth Rock, is 2HKOed by Fusion Bolt from the physically-biased set. Of course, it can also run a Substitute set, needing only a small amount of HP to grant 101 HP Substitutes, giving a nice "Fuck you" to Seismic Toss and also giving Kyurem-B a buffer to freely attack without worrying about Mach Punches or whatever, and it also has a Choice Scarf set (though admittedly this one is mostly for the surprise factor.) Just that versatility is like, "Okay, what set is he running? If he runs special, my Slowbro will have a good time, but if he runs physical, Slowbro's not doing so well against it... What do I do?" There is no way Kyurem-B is on the same level as stuff like passive-as-fuck Alomomola, overly-dependent-on-Rain Kabutops and Tornadus-T, and others, as they just can't cause your opponent to be faced with that dilemma. Of course, Kyurem-B doesn't do that nearly as effectively as Talonflame does, but that's why it's not up in A+ with Talonflame. Kyurem-B definitely deserves its rank.