This isn’t all-inclusive and it doesn’t go into the set / details or whatever, but I crawled through the UU Analyses and came up with some updates or minor suggestions.
Chesnaught;
Remove Trevenant from Checks and Counters, nobody uses that anymore.
Cloyster;
Could use a hazard setting set, even though Shell Smash is the main set. Also can use rapid spin, but weak to rocks and neutral to spikes make that a bad idea.
Donphan;
In Checks and Counters, there’s this;
“Ice-types: Ice-types only check Donphan, as they have to be wary of the rare Stone Edge. Also, most Ice-types lack significant bulk, so they can be KOed by a neutral hit.”
Why mention it if they get ko’d by a neutral hit then?
Entei;
Perhaps there can be mention of Liechi Berry + Natural Gift as a lure to stuff like Swampert or Rhyperior, both of which would normally stop it. The boost at low hp acts as a free band too, if you can keep it alive, it can switch attacks and clean late-game.
Forretress;
Checks and counters, Jirachi is in OU so it won’t be tricking it anything anytime soon. Still a relevant point though, maybe Espeon’s a better mon to put there in replacement?
Galvantula;
Other Options lists hp ice to hit Zygarde, but that’s banned. Raikou in Checks and Counters is OU, and Flygon is not a relevant mon to be in there.
Infernape;
Alakazam mentioned in checks and counters, though that may be a moot point with the next drops. Also, pretty much every mon bar fire types in checks fear a +2 Fire Blast or Grass Knot, being heavily dented on the switch if not outright ohko’d. Might be worth a mention?
Snorlax;
Checks and counters mentions both SD Celebi and Jirachi as a check.
Whimsicott;
I know it’s a fast special attacker, but Noivern is not relevant in the tier. Scarf Hydreigon would probably be a better example for that in C&C.