A couple of things I would like to see or stuff I agree with.
S Rank
Double Dance Lando-T should be put at A-. Although good it takes some support to function effectively in the metagame. This can be renamed so that it also includes sets such as Sub Salac Lando-T as well. I would just put Pivot as the category as it has both an offensive and defensive set and both are equally good at A+.
All Out Attacker set which includes Meteor Mash, Zen Headbutt, Hammer Arm, Grass Knot should be S because it is the most simplistic set to use and covers a lot of ground in the metagame. Its Rock Polish / Agility set is more along the lines of A+ to myself because bulky water types such as Slowbro are able to beat it on a more consistent basis due to loss of coverage. However there is the fact it's extremely tough to break once its traditional checks and counters are out of the big picture so I have no problems with seeing this S as well.
Calm Mind should be S because of the centralization it emphasizes in having a consistent answer to it. Utility set should be S as well because of the same reasons more or less but the fact that this set breaks stall a bit more effectively and punishes would be checks such as SD Garchomp and Talonflame real easily with Knock Off, Will-O-Wisp, Recover, Foul Play.
All Out Attacker I would put at S simply off of the simplicity factor and the optional 3rd coverage move in 2 STAB, Coverage, Fake Out. Sets such as Utility Attacker I would put at S. These sets include STAB + 2 support moves generally such as Sub + Baton Pass as one example or with Healing Wish. There's a lot of variances but off the bat these are the two categories I would use if you want something simple.
A+ Rank
Defensive Dragon Dance should be put at A-. It is one of the hardest sets to secure a sweep due to the nature of its utilization of mono attacking + support moves as such requires ample support to function. Offensive Dragon Dance I'd put at A+ because of its much more immediate fire power and coverage options. Support sets I would put at A+ such as the Hyper Voice, Roost, Heal Bell, Earthquake set as one example since it applies both offensive and defensive pressure where it is needed with a more defensive spread. Mixed Attacker M-Altaria should be ranked A+ simply because it encompasses variances in its sets varying from more specially offensive sets to ones that are actually mixed. This could include Special Attacker as well but I'll let you all decide.
No problems but please put Belly Drum at A+. Gaining Knock Off as a move tutor move amplified its effectiveness in the meta-game and it must be clearly established that this set is a serious threat to take into account for.
This looks good in A+ since all of its sets and the different variations are effective
Will-O-Wisp Zard-X should go to A-. It isn't so much being bad more of the fact it's not something that is as difficult to handle in the meta-game anymore. Bulky D-Dance should go to A, because of the dominance of Lando-T in the tier. Offensive Dragon Dance should have its set fixed to 104 HP / 220 Atk / 184 Speed Jolly Nature which is pretty much its most consistent spread right now. SD + Tailwind should be A and please remove the mentions of Fire Punch. It is mediocre on all of its sets with the exception of Will-O-Wisp and even then Flare Blitz provides it the necessary fire power to break balanced and defensive builds.
SR Clefable should be either moved to A- or put at A if you change SR Clefable to Support / Magic Guard Tank or something along the lines of that. SR Clefable by itself is bait for a lot of attackers and sets such as Moonblast, coverage, soft-boiled, Thunder Wave are perfectly legitimate. It should be differentiated in a way to emphasize this.
Life Orb Attacker should be at A+, I don't think this needs elaboration tbh.
This is fine in A+
To be perfectly honest with the exception of Choice Scarf Heatran all of its sets including an additional Fast Support set that you should add should be at A+. They're all equally good in regards to consistency from what I've been able to tell and use.
Choice Scarf should be removed to be honest. Not even sure why that was there in the first place when you have Lando-T.
Agreeing with Jukain that Sub CM should be A+. There's also Life Orb Keldeo that you could implement which has 3 attacks / Taunt and if so I would put this at A.
Fine for the time being even though I rather see this at A.
Either slash it on the Life Orb set or create a new one for Calm Mind Latios. This would go A by itself if you make it separate although I think a slash would be better.
SD + 3 attacks should be A+ as well. It's equal in effectiveness to its bulkier variant.
Looks fine
Looks fine