(Not ordered, besides S and S- rank)
Some reasonings:

I've been using these mons together as a physical defensive core, and they god damn rock. Mandibuzz with knock+toxic+foul play is able to assert a huge amount of pressure to offensive teams and can check gambit, moon, waterpon, tusk, sd gliscor and mixed pult. Toxapex meanwhile, can stuff a lot of physical attackers with rocky helmet, and beat cheesy calm mind stored power users with haze. Its list of things it can check are zama (hard walled), gambit (but can struggle with its immense power), waterpon, hamurott, primarina, cinderace, iron moth, weavile and meowscarada. I think people heavily underrated these mons, so I'm rating them highly.

Blissey I used on the same team, and its just a good wall. I think on fat teams you can afford this mon due to it walling most special attackers, so I'm rating it higher then the VR.

Mon is genuinelly not good, it competes with so many fairy types and struggles into offense if it doesn't have scarf. I don't see a reason to use this over other superior fairy types.

Before people come at me with pitchforks, I still think zama is amazing. However, it has so many checks/counters in the meta, and doesn't like the bulkier direction teams have gone. Still amazing, but compared to tusk and gambit, who do well against every team style, it has to be lower.

I will always hate on iron boulder. Ugly ass mon.

I've used this on a standard HO team, and it honestly feels a lot better then people are giving it credit for. It kinda wipes offensive teams thoroughly, who commonly stack fairy weak mons (especially sun lmao, who also usually only have one fairy resist that is weak to ground). This means it being forced to tera is not nearly as bad, as it can sometimes win the game on the spot (and it has enough bulk to take a big neutral physical hit if they tera). Really good mon that people underrated.

Keldeo has seen a resurgence lately as a great darkrai and kingambit check that can pivot while having decent damage. I have always thought that this mon was better then people were giving it credit for, and I'm glad I've been proven right on this part.