Noms of my own:
Smeargle for C
Yes I know, Shuckle is in C because it can sticky web multiple times, but whenever I use a webs team, I just find myself using smeargle. Access to spore, king/spike shield, parting shot, nuzzle etc just makes it so much nicer. Sure shuckle gets encore but then they just switch out, smeargle actually can threaten teams with the ability to baton pass. I dont really care if this moves up or Shuckle goes down, but smeargle is at least as good
Mew for A
Honestly, this thing is way too versatile (pun intended if you play TCG). The spdef set is a counter to lando, knock off cripples teams, it can break through stall with taunt, willo cripples offense.
http://replay.pokemonshowdown.com/ou-231735884 That replay shows me fucking around with sheddy the brokeness of stallbreaker mew. It beats his lando and clef sure, but it even takes on the scizor, and this is after being knocked off. Mew is really amazing in this role.
And that's just the stallbreaker set.
It can run nasty, sd, bulk up, calm mind, even barrier or amnesia if you're passing (like i said bp is broken). You can run all out attacking sets. Watching aim's latest video made me realize just how good this mon is. Sure the typing is bad but it is definitely better than celebi which is in A-, and has the same sort of splashability as rotom-w, which is in A, as opposed to stuff like volc sitting in A-. It also has tailwind boom, uturn, volt switch, trick, stealth rocks, defog. It just performs so many roles and certainly belongs higher than where it is