• Very strong matchups across-the-board
• Best counter to Vaporeon

Cons:

• Weak to Lapras

Optimal Moveset

• Dragon Breath + Dragon Claw

• Has no bad matchups

Cons:

• High potion usage

Optimal Moveset

• Lick + Hyper Beam or Body Slam OR
• Zen Headbutt + Hyper Beam

• Generally powerful attacker

Cons:

• Inefficient vs Fire Types
• Somewhat high potion usage

Optimal Moveset

• Frost Breath + Blizzard

• Strong counter to Vaporeon
• Extremely efficient when dodging

Cons:

• Relatively weak vs Fire Types

Optimal Moveset

• Zen Headbutt + Solar Beam

• Crushes everything that doesn’t directly resist fire
• Strong attacker into Lapras

Cons:

• Many gym players keep Arcanine in mind when choosing a defender
• Very weak to Vaporeon, the most common gym defender

Optimal Moveset

• Fire Fang or Bite + Fire Blast

• Powerful metagame-defining attacker vs all who don’t resist water (and some who do)

Cons:

• Weakness to the big 4 grasses: Exeggutor, Venusaur, Vileplume, Victreebel
• Knowledgeable gym players focus on countering him
• Somewhat high potion usage

Optimal Moveset

• Water Gun + Hydro Pump or Aqua Tail

• Hard counters Vaporeon and other waters
• Hard counters rock/ground types

Cons:

• Weak vs Arcanine and Dragonite

Optimal Moveset

• Vine Whip + Solar Beam or Petal Blizzard

• Strong overall attacker with coverage provided by Psychic

Cons:

• Weak vs the big grasses

Optimal Moveset

• Water Gun + Psychic

• Hard counters Vaporeon and other waters
• Incredibly efficient when dodging

Cons:

• Weak vs Arcanine and Dragonite

Optimal Moveset

• Razor Leaf + Solar Beam or Leaf Blade

• Slightly weaker version of Vaporeon

Cons:

• Slightly weaker version of Vaporeon

Optimal Moveset

• Water Gun + Hydro Pump

• If you managed to get a Dragon Breath + Dragon Pulse variant while it was available, it is a strong overall attacker as well as a decent Dragonite counter
• Bite + Hydro Pump (best currently evolvable moveset) leaves Gyarados as just another strong attacker vs Pokemon that don’t resist water

Cons:

• Electrics are good vs almost nothing except Gyarados. Don’t attack Electrics.

Optimal Moveset

• Bite + Hydro Pump OR
• Dragon Breath + Hydro Pump or Dragon Pulse

• Best available counter to Fairy Types
• Very strong counter to Grass and Bug Types

Cons:

• Weak to Ground and Psychics

Optimal Moveset

• Poison Jab + Sludge Wave or Gunk Shot

• Earthquake moveset very powerful vs Fire, Electric, Poison, Rock, and Ghost
• Sludge Wave moveset very powerful vs Fairy and Bug
• No bad movesets

Cons:

• Weak vs Vaporeon and other waters, as well as Exeggutor and other Psychics

Optimal Moveset

• Bite + Earthquake OR
• Poison Jab + Earthquake

• Overall consistent matchups
• Low CP yields high prestige per win
• Battles well vs Dragonite with Dragon Breath

Cons:

• Doesn’t hit quite as hard as the rest of the tier
• High potion usage

Optimal Moveset

• Pound + Hyper Beam or Play Rough

• Consistently strong defense vs any attacker.
• Strengthens any gym, regardless of region or defenders already present.
• Presence deters attackers.

Cons:

• None.

Optimal Moveset

• Zen Headbutt + Hyper Beam or Body Slam

• Water/Ice typing is synergistic; powerful STAB Ice moves protect Water’s weaknesses.
• Matches up favorably against a huge array of popular attackers.
• Elite base stats.
• Incredibly direct Dragonite counter.

Cons:

• Arcanine can do relatively well against, but not crush, Lapras.

Optimal Moveset

• Ice Shard + Blizzard or Ice Beam

• Very strong defender against Vaporeon.
• Highest base stats of any Pokemon currently available.
• Incredibly high CP adds a psychological deterrent.
• Resistance to Fire, Water, and double resistance to Grass cover most of the popular attackers.

Cons:

• Double weakness to Ice leaves him highly vulnerable to Lapras and to a lesser extent Dewgong and Cloyster.

Optimal Moveset

• Steel Wing + Dragon Pulse

• Typing is near-perfection for the current metagame; provides resistance to Fire and Water as well as access to STAB Psychic moves.
• Psychic moves are resisted only by Psychic and Steel Pokemon in this generation.
• Type-disadvantages vs Bug, Electric, Ghost, and Dark are EASILY overcome due to a lack of elite attackers of those types
• Favorable matchup vs Vaporeon

Cons:

• Base stats are very good but not elite.
• Though no Pokemon is a direct counter, Exeggutor with Solar Beam or Seed Bomb does well.

Optimal Moveset

• Confusion + Psychic

• Poliwrath matches up favorably against approximately as many Pokemon as the Tier 1 Pokemon do.
• Bubble is awkward to dodge and is the strongest basic attack in the game.
• Mathematically superior to Vaporeon on defense, also matches up favorably vs attacking Vaporeon.
• Fighting type provides helpful resistance to Rock.
• Ice Punch, though suboptimal in most matchups, is the best against Grass-type attackers who are likely to be used against Poliwrath.

Cons:

• Unfavorable matchups vs the big grass types, especially Venusaur and the relatively popular Exeggutor, keep him out of Tier 1.

Optimal Moveset

• Bubble + Ice Punch or Hydro Pump or Submission

• No Pokemon in the game is better against Vaporeon than Exeggutor
• Did you catch that Exeggutor is the best available counter to Vaporeon?!
• Grass moves are not necessary. (Who attacks into Exeggutor with a Pokemon weak to Grass?)
• Confusion + Psychic provides immense STAB type-coverage, and punishes all attackers regardless of type (while still maintaining the favorable matchup vs Vaporeon).

Cons:

• Arcanine can do well against Exeggutors, especially ones with Solar Beam and Seed Bomb.

Optimal Moveset

• Confusion + Psychic or Seed Bomb or Solar Beam (especially against Waters)

• Normal/Fairy type is very consistent and impossible to efficiently exploit with an elite attacker.
• Extremely CP-efficient defender.
• Counters Dragonite.
• Essentially nothing hard counters Wigglytuff.
• Mini-Snorlax.

Cons:

• Low CP value may invite more attempts at your gym.
• Soft-countered by Nidoqueen and Muk.

Optimal Moveset

• Pound + Play Rough

• Singlehandedly dictates the gym metagame due to raw popularity and ease to obtain.
• Elite base stats and strong defensive typing.
• Isn’t too bad at defending against Vaporeon.
• Defends very well against anything that doesn’t type-counter it.
• Strong psychological deterrent due to community’s perception.

Cons:

• Water Gun is a quite poor attack when considering Gym Defense AI.
• Strongly countered by the big grasses: Exeggutor and Venusaur.
• Strongly countered by Dragonite.
• Soft-countered by Vileplume and Victreebel.
• Everyone has practiced dodging Vaporeon’s moves.

Optimal Moveset

• Water Gun + Water Pulse (Aqua Tail and Hydro Pump also serviceable)

• Hard counters Waters including Vaporeon.
• Hard counters the top Rock/Ground types Golem and Rhydon.
• Efficient moveset and very good base stats handle most attackers that don’t type-counter Venusaur.
• Sludge Bomb can be used for better type-coverage vs Venusaur’s counters while still maintaining a favorable matchup vs Vaporeon.
• Amazingly manages a favorable matchup vs Flareon.

Cons:

• Hard-countered by Dragonite and Charizard.
• Soft-countered by Arcanine and Lapras.

Optimal Moveset

• Razor Leaf + Sludge Bomb

• Fantastic typing matches up very well against multiple elite attackers.
• Rock Slide’s long duration and low energy requirement allow Omastar to be STAB Rock Sliding almost non-stop during the fight.
• Double-resists fire.
• Counters Lapras !
• Counters Dragonite !

Cons:

• Double-weakness to Grass leaves him punished by Exeggutor, Venusar, Vileplume, and Victreebel.
• Low CP and highly-underrated community perception of Omastar may invite more attackers (though this is counterbalanced by the joy you will feel seeing attackers getting beaten back by Omastar)

Optimal Moveset

• Water Gun + Rock Slide

• Elite base stats featuring a monsterous attack value will crush absolutely any Pokemon that doesn’t resist Fire.
• High CP may deter potential attackers.
• No Grass Shall Pass.

Cons:

• Fire is a disastrous defensive typing in Pokemon Go.
• Gets run over by Vaporeon and the other relevant Water Gun users such as Blastoise, Slowbro, Golduck, Omastar, etc.
• Also countered by Rhydon, Golem, and Poliwrath.

Optimal Moveset

• Fire Fang + Flamethrower

• See Venusaur, just ever so slightly weaker. Victreebel does exactly what Venusaur does just a little bit worse due to her lowered effective health. Victreebel packs more of a punch than Venusaur, but not quite enough to make up for the lowered tankiness.
• Crushes Vaporeon.
• Manages a barely positive matchup vs Flareon.

Cons:

• Hard-countered by Dragonite and Charizard.
• Countered by Arcanine and Lapras

Optimal Moveset

• Razor Leaf + Sludge Bomb (or Leaf Blade or Solar Beam to all-in against Waters)

• See Venusaur (minus the Sludge Bomb comment). Vileplume does exactly what Venusaur does just a little bit worse due to her lowered effective health that is not quite compensated strongly enough by her slightly increased attack stat.
• Crushes Vaporeon.
• Manages a barely positive matchup vs Flareon.

Cons:

• Hard-countered by Dragonite and Charizard.
• Countered by Arcanine and Lapras.

Optimal Moveset

• Razor Leaf + Petal Blizzard

• Benefits from the largely-unresisted STAB Confusion + Psychic combo.
• No elite (or very good) attacker attacks Super-Effectively into Hypno.

Cons:

• Despite winning so many matchups, middling base stats prevent Hypno from dominating these attackers and preserving high health for the next attacking Pokemon.
• Low CP and underwhelming community reputation may invite attackers.

Optimal Moveset

• Confusion + Psychic and Psyshock

• Pound, Zen Headbutt and Dazzling Gleam have consistent coverage over the relevant attackers and are rarely resisted.
• Dazzling Gleam’s long cooldown and low energy requirement let Clefable spam it almost constantly on defense.
• Fairy typing is consistent and difficult to type counter with elite attackers in PoGo.
• Relatively strong counter to Dragonite

Cons:

• Base stats are good but not great.
• Similarly to Hypno, does not utterly dominate many matchups due to neutral typing.

Optimal Moveset

• Pound or Zen Headbutt + Dazzling Gleam