Okay, get ready for the dumbest question ever.
What the hell IS the tier list right now?
Before you link me to Smogon's Pokédex, let me clarify, because Smogon's Dex doesn't actually help. I mean to ask what exactly is banned and what isn't. It's been a long time since I've done competitive battling (I've been on hiatus), and I just want to know what I can and can't use in any given tier.
Smogon's Pokédex says that I can use Kangaskhan in NU, but its Mega can only be used in Ubers. Smogon's Pokédex says that Ninetales is NU, but its ability can only be used in OU. Smogon's Pokédex mentions nothing on the legality of Baton Pass Chains, Swagger, etc.
And it seems like every tier has plenty of such weird complex miscellaneous exceptions that, as far as I can tell, are not documented anywhere. The only way to know about them is to have been playing consistently since the start of Gen 6 and just keeping an eye on it as it happens. This makes it difficult for new or returning players, so if someone could please clarify this for me, that'd be great.