As someone who has played water extensively since the start, these are my thoughts:
(1) Dondonzo -> S
This fish is just ridiculous. Any Pokémon that can single-handedly bail a player out of a losing situation deserves the ultimate ranking. Invest some Sp.Def and nothing kills her without dying first after she secures a Curse or two
(2) Toxapex-> A
She got nerfed badly this generation without Knock Off and the ability to fish for burns. Toxapex is still not useless, though, as she still can set Toxic
Spikes, Haze, and just being hard as fuck to kill
(3) Azumarill -> A
Sap Sipper is a godsend against powerhouses like Breloom. Without Azumarill, water teams get completely wrecked by the mushroom. I’m not even gonna bother saying anything about grass teams
				
			(1) Dondonzo -> S
This fish is just ridiculous. Any Pokémon that can single-handedly bail a player out of a losing situation deserves the ultimate ranking. Invest some Sp.Def and nothing kills her without dying first after she secures a Curse or two
(2) Toxapex-> A
She got nerfed badly this generation without Knock Off and the ability to fish for burns. Toxapex is still not useless, though, as she still can set Toxic
Spikes, Haze, and just being hard as fuck to kill
(3) Azumarill -> A
Sap Sipper is a godsend against powerhouses like Breloom. Without Azumarill, water teams get completely wrecked by the mushroom. I’m not even gonna bother saying anything about grass teams
 
 
		


 
 
		 B --> A
 B --> A 
 
		





 UR ---> B
 UR ---> B B ---> A
 B ---> A A ---> C
 A ---> C 
 
		



 
	 
	 
 
		 
	 
	 
	 
 
		 
	 
	 
	 
 
		








 
 
		 
 
		 
 
		 
 
		 
	 
	 
	 
	 
 
		





 A-> S (The catto is the second fastest scarfer right now, and its ability to force switches, revenge-kill meanies like Scarf Valiant and Specs Flutter Mane, and clean types late-game is unparalleled. It can also fit in Spikes or Trick in a pinch too, making it a great last-ditch effort in murking walls like Toxapex in a pinch. Or just u-turn and bring in something like Hydrei to take advantage of those)
 A-> S (The catto is the second fastest scarfer right now, and its ability to force switches, revenge-kill meanies like Scarf Valiant and Specs Flutter Mane, and clean types late-game is unparalleled. It can also fit in Spikes or Trick in a pinch too, making it a great last-ditch effort in murking walls like Toxapex in a pinch. Or just u-turn and bring in something like Hydrei to take advantage of those) S-> A/B (Rapid Spin and Knock Off good, Shed Tail isnt as amazing in Monotype, as you almost always need Multiscale Dragonite if your shed tail is going anywhere. Dragalge is usually a better pick as it covers random Fairy-types which Dragon-types usually can't handle as well)
 S-> A/B (Rapid Spin and Knock Off good, Shed Tail isnt as amazing in Monotype, as you almost always need Multiscale Dragonite if your shed tail is going anywhere. Dragalge is usually a better pick as it covers random Fairy-types which Dragon-types usually can't handle as well) A (Catgon helps so much for Dragon teams as he provides a good Chien Pao, Baxcalibur, and Scizor answer with a Choice Scarf set. He's also a decently fast scarfer if you don't want scarf Dragapult / Roaring Moon, though this comes at the cost of not being able to pivot. It can also run wallbreaking sets with a Choice Specs, but Specs Pult does it better, with the exception of Ting-Lu hating Walky Wakey much, much more)
 A (Catgon helps so much for Dragon teams as he provides a good Chien Pao, Baxcalibur, and Scizor answer with a Choice Scarf set. He's also a decently fast scarfer if you don't want scarf Dragapult / Roaring Moon, though this comes at the cost of not being able to pivot. It can also run wallbreaking sets with a Choice Specs, but Specs Pult does it better, with the exception of Ting-Lu hating Walky Wakey much, much more) C->A (Deals with fast threats like Greninja and Iron Valiant which nom Electric teams and is also a cool Ground immunity. Just don't count on it hitting Hurricanes, though. Also helps since he's the fastest viable Electric guy)
 C->A (Deals with fast threats like Greninja and Iron Valiant which nom Electric teams and is also a cool Ground immunity. Just don't count on it hitting Hurricanes, though. Also helps since he's the fastest viable Electric guy) B->C (Is a liability, activating opposing team's Quark Drive for very little returns is not fun)
 B->C (Is a liability, activating opposing team's Quark Drive for very little returns is not fun) UR->C (Electromorphosis with Soak isn't too bad + Electric struggles to field 6 good mons anyways. Checking Chien-Pao and Azumarill in a pinch is also great)
 UR->C (Electromorphosis with Soak isn't too bad + Electric struggles to field 6 good mons anyways. Checking Chien-Pao and Azumarill in a pinch is also great) A->B (He's a disappointment, or a work in progress.)
 A->B (He's a disappointment, or a work in progress.) B->A (Also mentioned by Mush, would like to add that it has the ability to win against almost all Physical attackers and is currently fighting a speedcreep war to keep Kingambit in check)
 B->A (Also mentioned by Mush, would like to add that it has the ability to win against almost all Physical attackers and is currently fighting a speedcreep war to keep Kingambit in check) A (Diguising as bulky stuff like Skele and Focus Missing Greninja, Disguise as Flutt and trick Corviknight, Disguise is disgusting and this makes Ghost teams a bit more fun to play)
 A (Diguising as bulky stuff like Skele and Focus Missing Greninja, Disguise as Flutt and trick Corviknight, Disguise is disgusting and this makes Ghost teams a bit more fun to play) 
 
		
 
  UR -> A for Flying
 UR -> A for Flying 
 
		
 B->A
 B->A UR->B
 UR->B 
 
		 S -> A
 S -> A A -> S
 A -> S B ---> A (Fire)
 B ---> A (Fire) B ---> A (Rock)
 B ---> A (Rock) 
 
		 
	 
	 
  
  
  
	 
	 Lokix
Lokix Slither Wing
Slither Wing 
	 
	 
	 
	 Rabsca
Rabsca Venomoth
 Venomoth Chien-Pao
Chien-Pao Ting-Lu
Ting-Lu 
	 
	 
	 Kingambit
Kingambit 
	 Roaring Moon
 Roaring Moon 
	 Brute Bonnet
 Brute Bonnet Iron Jugulis
Iron Jugulis 
	 
	 
	 Wo-Chien
Wo-Chien Baxcalibur
Baxcalibur 
	 
	 
	 
	 
	 
	 
	 
	 Tatsugiri
Tatsugiri Iron Hands
Iron Hands Rotom-Wash
Rotom-Wash 
	 Pawmot
Pawmot Sandy Shocks
Sandy Shocks Oricorio Pom
Oricorio Pom 
	 Rotom-Mow
Rotom-Mow 
	 
	 
	 
	 
	 Rotom-Frost
Rotom-Frost Flutter Mane
Flutter Mane 
	 
	 
	 Iron Valiant
Iron Valiant 
	 
	 Tinkaton
Tinkaton Scream Tail
Scream Tail 
	 Great Tusk
Great Tusk 
	 
	 
	 
	 Tauros-Paldea-F
 Tauros-Paldea-F 
	 
	 
	 Iron Moth
Iron Moth Ceruledge
Ceruledge Arcanine
 Arcanine Armarouge
Armarouge Charizard
 Charizard 
	 
	 
	 
	 Bombirdier
 Bombirdier 
	 
	 Gholdengo
Gholdengo Brambleghast
Brambleghast 
	 Gengar
Gengar 
	 
	 
	 
	 Toedscruel
Toedscruel Arboliva
Arboliva 
	 
	 Scovillain
Scovillain 
	 Clodsire
Clodsire 
	 Iron Treads
Iron Treads 
	 
	 
	 Cloyster
Cloyster 
	 
	 
	 
	 
	 Maushold
Maushold 
	 
	 
	 Farigiraf
Farigiraf Grafaiai
Grafaiai 
	 
	 Glimmora
Glimmora 
	 Revavroom
Revavroom Haunter
Haunter 
	 
	 Espathra
Espathra Slowbro
Slowbro 
	 Garganacl
Garganacl 
	 
	 
	 Klawf
Klawf 
	 Orthworm
Orthworm Dondozo
Dondozo 
	 
	 
	 Tauros-Paldea-W
 Tauros-Paldea-W Veluza
Veluza 
 
		