Type: Electric
Abilities: Electric Surge
Base Stats: 70 HP / 115 Atk / 85 Def / 95 SpA / 75 SpD / 130 Spe
Tapu Koko is extremely fast!! It outspeeds the majority of Pokemon it encounters and almost always will make the first move. Despite its average Special Attack stat, Electric Terrain gives it a very strong Thunderbolt. However, low power on its coverage moves makes it difficult for it to break past Pokemon that resist Electric. Its coverage, while not spectacular, has everything it needs to hit the vast majority of the tier. Its Fairy typing helps it defensively by giving it useful resistances to Fighting and Dark and an immunity to Dragon, letting it switch into Pokemon like Tornadus-T, Thundurus, and Weavile very easily. Electric Terrain provides minor team support by preventing Pokemon like Tangrowth and Amoonguss from putting its teammates to sleep and crippling opposing Tapu Lele and Bulu in a pinch.

Type: Poison / Dark
Abilities: Poison Touch / Power of Alcemy
Base Stats: 105 HP / 140 Atk / 95 Def / 55 SpA / 65 SpD / 45 Spe
Alolan Muk has an excellent typing that provides 4 useful resistances and an immunity to Psychic, which combined with its good 100/105 special bulk makes it a safe switch-in to many Psychic-type Pokemon such as Tapu Lele and Mega Alakazam. STAB Pursuit allows Alolan Muk to effectively trap Psychic-types and either KO or severely cripple them on the switch. STAB Knock Off hits hard and complements Alolan Muk's Poison-type STAB moves by being able to cripple Steel-types. Muk has a respectable chance to spread poison by its ability, Poison Touch. This allows it to potentially cripple normally safe switch-ins before being forced out. One of my favorite sets to run with Muk is a Curse set. Curse is a move that increases both its attack and defense stats while lowering its speed. This potentially turns Alolan-Muk into a sweeper similar to Garchomp. However, Alolan-Muk is incredibly weak to Ground-types, and has no real way to threaten them.

Type: Psychic
Abilities: Synchronize / Inner Focus / Magic Guard
Base Stats: 55 HP / 50 Atk / 45 Def / 135 SpA / 85 SpD / 120 Spe
With high speed and special attack, an offensive set for Alakazam should go without saying. Having a STAB attack should be obvious, and Alakazam has two viable choices. Psychic packs more power and can on occasion get lucky with a special defense drop, while Psyshock can target the opponent’s defense, allowing a slightly easier time getting around special walls. However, there’s a few obvious gaps in Psychic coverage. The most obvious of which is Dark types and Steel types, both of whom are handled by Focus Blast, which for the former can often be the only thing standing between Alakazam and a Pursuit trapping. Shadow Ball is next up on the coverage list, as it hits opposing Psychic types hard, in addition to dealing super effective damage against Ghosts as well. For the final moveslot, Alakazam has a few options available to it. Encore can be used to troll some of the more passive Pokemon, in addition to messing with Substitute users and things trying to set up.

Type: Water
Abilities: Schooling
Base Stats: 45 HP / 140 Atk / 130 Def / 140 SpA / 135 SpD / 30 Spe
Taking its School Form as the original form, this Pokemon essentially is an Archeops with a more lenient condition and a less forgiving consequence. However, we can look at what School Form has to offer, and we see that there is plenty of it. For starters, Base 140 offenses and 45/130/135 defenses are nothing to laugh at, and it will take considerable effort to get Wishiwashi into Solo Form. Furthermore, with a powerful STAB Hydro Pump and sufficient coverage options, this Pokémon is guaranteed to put a dent in something, at the very minimum. A Hydro Pump coming off of a 140 base Special Attack, with Ice Beam for coverage, is nothing to scoff at, especially if it is guaranteed to 3HKO Mew with maximum Special Defense investment. With 140 base Attack as well, Earthquake makes it easy to take care of problematic Steel-type Pokémon, and is notable for hitting Toxapex super effectively.

Type: Water / Bug
Abilities: Water Bubble
Base Stats: 55 HP / 50 Atk / 45 Def / 135 SpA / 85 SpD / 120 Spe
Water Bubble prevents burns, halves Fire-type moves' damage, and doubles the power of Araquanid's Water-type moves. Put all these together with Water-type STAB, and Araquanid is going to deal serious damage even to Pokemon that resist Liquidation, and its offensive power cannot be easily hindered. Impressive Special Defense lets it tank strong hits, and even some super effective ones; for example, Nihilego's Power Gem after a Beast Boost only has a 50% chance to OHKO. Its low Speed lets it perform very well under Trick Room. However, low offensive stats leave its other moves noticeably lacking in power. It's tough to be a Bug-type in a metagame with Tapu Koko, Kartana, and Tapu Fini, which can all easily counter it. Araquanid is rather easy to predict, as it only has one reliable role.

Type: Water / Posion
Abilities: Synchronize / Inner Focus / Magic Guard
Base Stats: 50 HP / 53 Atk / 62 Def / 43 SpA / 52 SpD / 45 Spe
Mareanie's fantastic defensive ability in Regenerator alongside its decent mixed bulk, access to reliable recovery, and typing allow it to function on balanced and defensive teams as a stellar defensive pivot as well as a safe switch-in to common threats. Scald is a useful STAB attack that has a decent chance to burn physical attackers. Sludge Bomb is a good STAB attack that hits Fairy- and Grass- types. Recover provides Mareanie with an impressive amount of longevity and, alongside Regenerator, allows it to sustain itself throughout a battle and stall out status-inflicted foes. Toxic Spikes allows Mareanie to support its teammates by poisoning foes; thanks to Regenerator, it is able to be set up consistently throughout a match. Haze can be used over Sludge Bomb or Toxic Spikes in order to help Mareanie deal with threatening setup sweepers in Swords Dance Garchomp by removing its stat boosts.

Type: Fire / Steel
Abilities: Full Metal Body
Base Stats: 137 HP / 137 Att / 107 Def / 113 SpA / 89 SpD / 97 Spe
Solgaleo is able to counter many Xerneas variants by virtue of its typing and above average defensive stats. It has access to reliable recovery via Morning Sun, which is rare among Xerneas answers. An above average Attack stat allows Solgaleo to run offensive sets, KOing Xerneas after a bit of prior damage or putting it into range of priority moves. Its wide coverage allows it to hit the vast majority of the metagame for decent damage. It is able to deal with Deoxys-A well, countering variants that do not carry Knock Off. An excellent ability in Full Metal Body allows Solgaleo to avoid Attack and Speed drops from Intimidate and Sticky Web. Solgaleo is hindered by its weakness to Ghost-types, which leaves it vulnerable to being revenge killed by Mega Gengar. Weaknesses to Ground- and Dark-types, two of the most viable types in the tier, do not help Solgaleo's defensive utility. It lacks the power to break through some walls, as Steel / Psychic is not the best offensive typing in the metagame.

Type: Psychic / Ghost
Abilities: Shadow Shield
Base Stats: 137 HP / 113 Atk / 89 Def / 137 SpA / 107 SpD / 97 Spe
Lunala has decent Speed and good Special Attack stats, making it an ideal wallbreaker. It possesses good coverage between its STAB moves along with options like Moonblast and Focus Blast. Shadow Shield reduces the damage Lunala takes by half if Lunala is at full HP, and it is not affected by Mold Breaker abilities, which gives Lunala fantastic bulk at full HP. While good offensively, Psychic / Ghost is among the worst defensive typings in the game. Due to its 4x weakness and lack of a powerful STAB move to deal with them, Lunala hates Dark-type Pokemon for their ability to do huge damage to it with ease while preventing it from spamming its STAB moves, although it does have the coverage options to beat most Dark-types in certain situations. Despite this, the immunities it does have enable it to be a good Choice Scarf Pokemon and have a good matchup versus offense. Lunala suffers from being just slower than some common threats, most noticeably Yveltal and Adamant Mega Lucario.