Carracosta to
S
Carracosta is a meta defining threat without a doubt, but since it was S, the meta has been more prepared for it, ie every one runs Poliwrath. However, recently, the defensive set has got a lot better, as it switches into a broken and a semi-broken pokemon, tauros and sneasel (this shouldnt be understated), and has a good typing in general, so it can chack other physical attackers like barbaracle and bouffalant. The shell smash set is liking this meta even more, as firstly, Poliwrath usage has been going down, as more people are using throh (and zen headbutt INNOVATION), and ninetales is also shown to be great in this meta, who is a great team mates, since it can set up on tangela who it baits in, and can hit bulky water types hard (before any one nitpicks, this shows that it is easy to weaken costa's checks and counters)
Simisage to
B/B-
Serperior leaving was heaven for this, as the main competition for a team slot came from serp, now its small niche, in hitting bouff and others with focus blast, is much larger, as it can successfully run a nasty plot set and sub seed without any competition. These sets arent too bad in this meta, as nasty plot + giga drain and life orb is pretty strong, and its speed backs this up nicely, allowing it to outrun ninetales and dodrio. Grass is a very important type in this meta as water types are very common, and simisage uses the second best poke in the tier as set up fodder. Mixed bait sets are also decent as it has a pretty wide movepool with tools like knock off to beat roselia, etc. Sage does have some weaknesses, ie sneasel, scyther, tauros and other faster pokes, but im only suggesting a bit of a promotion
Kecleon
S (maybe
A+)
Im not gonna say too much about this as it will probably leave the tier soon, but this mon is so broken lol. It demolishes offensive teams as fighting + dark coverage is very good, considering how fairy types arent very common, and its decent attack stat combined with STAB on everything makes it a really strong threat. Its strong priority is what makes it so amazing, as sucker punch is very strong, and not many offensive mons can take sucker + fake out or any other move + sucker for that matter. Its main switch ins are also crippled by knock off, and even other checks also hate losing lefties, eg torterra.
Rotom-F
A+
Rotom-F is very good in this meta, as momentum is very important now considering the tier is dominated with offensive based teams. Scarf sets are always solid, as it hits hard even with volt switch, which can be bought in to either KO a poke or gain momentum. Piloswine is also the only ground poke that will try to block a volt switch, but that gets heavily crippled by trick, and laughed at by willo/subsplit. Continuing to that, subsplit is amazing in this meta, as it messes with any defensive teams and offensive based ones (unless pilo :L) lack anything to take a life orb thunderbolt or blizzard. Ive been using a specs set lately, which is also great as it has amazing power, and it is very easy to bluff scarf and force the poke out and gain momentum.