So, by asking what Water Types are good for a playthrough, I’m guessing you mean offensive, so I’m going with some of the best offensive water types with good coverage.
Physical Attackers
Barraskewda
Barraskewda is a punishing physical attacker with a speed stat that will allow you to outspeed nearly all the competition. You can learn powerful moves such as Liquidation and Crunch. With TRs, you can get great coverage with Psychic Fangs, Close Combat, and Poison Fang, and Drill Run, allowing you to smash Opal, Melony, and Piers. The combination of Crunch and Poison Jab will allow you sweep Allister. Poison Jab is also great against Bede.
Gyarados
If you can live with Magikarp for a couple of the first gyms, Gyarados will pay off. Gyarados probably has the best movepool if you’re struggling to get / find TMs or TRs. You get Waterfall as powerful STAB and access to coverage in Ice Fang and Crunch. You get the all-powerful setup move in Dragon Dance at Lv. 36. The only TR you could really use is Earthquake. Ice Fang can cleanly wipe out about half of Raihan’s team. Gyarados can probably handle about every trainer but Melony, but that’s why you have 6 Pokémon now.
Special Attackers
Inteleon
Yeah, the Pokémon is a starter, of course it’s going to be good. Inteleon is like a special Barraskewda that’s a bit bulkier and has less coverage. This Pokémon has nothing on Milo when it’s Sobble or Melony later on. Snipe Shot is your signature move, but honestly not much better than Waterfall on Gyarados. You’ll be a little reliant on TMs, needing Ice Beam for some coverage and Shadow Ball for Allister. Raihan and Piers could be difficult without many ways to hit them Super Effectively, but if you play right it should be fine.
Pelipper
Pelipper has one thing going for it that makes it relevant. Drizzle, although in order to find one you might have to evolve a few Wingulls to get one. Pelipper gets some powerful attacks in Hurricane and Hydro Pump, though they come quite late. So until then you have mediocre STABs in Water Pulse and Air Slash. Through TMs you can get coverage in Ice Beam. You’ll have neutral matches vs Allister and Opal. The place where Pelipper proves its value is Kabu and Raihan. Pelipper can swap in and take away the weather conditions that give those gym leaders an advantage.
Against Gym Leaders:
This is based what gyms each Pokémon can easily deal with:
Good Against:
Barraskewda: Kabu, Allister, Opal, Melony, Piers
Gyarados: Kabu, Allister, Piers, Raihan
Inteleon: Kabu, Allister, Raihan
Pelipper: Milo(Wing Attack), Kabu, Raihan
Okay against:
Barraskewda: Milo(Peck), Nessa
Gyarados: None
Inteleon: Nessa, Opal
Pelipper: Allister, Piers
Bad Against
Barraskewda: None
Gyarados: Milo and Nessa(you be Magikarp), Melony
Inteleon: Milo, Melony
Pelipper: Nesssa(Drednaw), Melony
Good-3
Okay-2
Bad-1
1-Barraskewda-19
2-Pelipper-15 Inteleon-15 Gyarados-15
Some other notes:
Barraskewda is probably the most TM / TR reliant, while Gyarados is the least. Inteleon probably has the worst coverage, and Barraskewda the best. All four of these Pokémon are easy to obtain, although Pelipper with Drizzle is probably the hardest one to get.
Final Notes
The best choice is either Barraskewda or Gyarados. Pelipper’s only niche is Drizzle and its good attack moves come really late. Inteleon has terrible coverage. Inteleon also takes a valuable starter spot that you could use for Rillaboom or Cinderance instead. Barraskewda if you don’t mind getting the TMs for coverage. Gyarados if you would rather not be TM reliant. Hope this helped!
