I've chose Collin Heier's team from the Dallas Regionals. I chose it because it had a few Pokemon I've been trying to use in the VGC Showdown metagame and in Doubles. He also got a pretty high place in the tournament, so this team must've really worked out for him! I also noticed that most of the teammates compliment each other when paired up (usually by taking care of each other's weaknesses), and the team has at least one resistance or immunity to every type.
I also think this is a Trick Room team, since it has Porygon 2 (a common TR setter) and pretty slow Pokemon.
Tapu Fini
Tapu Fini @ Iapapa Berry
Ability: Misty Surge
EVs: 240 HP / 108 Def / 132 SpA / 28 SpD
IVs: 0 Spe
Modest Nature
- Calm Mind
- Muddy Water
- Moonblast
- Protect
Tapu Fini is a bulky Pokemon that's slow enough to abuse a Trick Room Team. I'm using the regular Fini set, except without the 4 Speed EVS. Instead, the 4 EV remainders are put into HP. The Iapapa Berry is used for healing, and Modest doesn't reduce its Defense. 240 HP, 108 Defense, and 28 EVs are for increased bulk. The remainder is put into the Special Attack, to make Tapu Fini hit harder. This EV spread helps Tapu Fini survive a Tectonic Rage from Landorus-T, and then OHKO him with Muddy Water. It can also survive Timid Tapu Koko's Thunderbolt. Calm Mind helps Tapu Fini hit harder and take hits better. Muddy Water is for Water STAB and dealing with Rock, Fire and Ground, something this team may have trouble with. The lowered accuracy is also useful. Moonblast is for Fairy STAB and Protect is for protecting itself against ally moves (especially Vikavolt's Discharge!) and other attacks.
And just saying: all the Pokemon on this team have 0 IVs so they can take full advantage of Trick Room.
Tapu Fini when paired with Arcanine deals with Rock and Ground for him, while Arcanine takes care of Grass for it. With Garchomp, Fini deals with Dragon types and Garchomp deals with Electric and Poison types for Fini. With Metagross, Fini deals with its Fire, Dark, and Ground weaknesses. When paired with Vikavolt, Tapu Fini can deal with the Rock and Fire types that threaten Vikavolt. Meanwhile, Vikavolt can deal with Grass types that can threaten Tapu Fini and other Water types Fini may struggle to take out.
Arcanine:
Arcanine @ Aguav Berry
Ability: Intimidate
EVs: 244 HP / 188 Def / 76 SpD
IVs: 0 Spe
Calm Nature
- Flamethrower
- Snarl
- Will-O-Wisp
- Morning Sun
Arcanine is a bulky Pokemon that can weaken both physical and special attackers with Intimidate+Snarl+Will-O-Wisp. The EVs for HP are made divisible by 4 so the Aguav Berry will activate after Guardian of Alola. With 188 Defense, Arcanine can survive a 3HKO Earthquake from Garchomp after Aguav Berry and Intimidate. A Calm nature combined with 76 EVs in Special Defense lets it survive a Life Orb Tapu Lele's Psychic in Psychic Terrain or Salamence's Devastating Drake. Flamethrower is for Fire STAB and to deal with some of the Grass and Ice weaknesses my team suffers from. Snarl is to weaken Special Attackers who don't mind a Will-O-Wisp and an Intimidate. Will-O-Wisp weakens opponents quicker and does chip damage, and Morning Sun is for reliable recovery even after the Aguav Berry is used.
Arcanine deals with Ice types for Garchomp, and Garchomp deals with Rock types. Metagross deals with Rock types and Arcanine can attack Ghost types with Snarl. Vikavolt can deal with Water types and Ground types (will explain later). Arcanine weakening the opposing team will probably help the team in the long run.
Garchomp:
Garchomp @ Garchompite
Ability: Rough Skin
EVs: 252 HP / 252 Atk / 4 Def
Brave Nature
IVs: 0 Spe
- Earthquake
- Dragon Claw
- Poison Jab
- Protect
Let me explain: While Mega Garchomp does improve some of regular Garchomp's stats, it loses speed. That is why nobody uses it. However, with a Trick Room team, that's perfect. You get a stronger, bulkier Pokemon that's slow enough for a Trick Room team. Therefore, I think this is a Mega Garchomp. Rough Skin is to punish physical attackers. I can switch out a Pokemon for Mega Garchomp and when an opposing Pokemon attacks Garchomp, they get punished with Rough Skin. I have 252 HP and 4 Defense for a bit of bulk, and 252 Attack that allows Garchomp to hit as hard as possible. A Brave Nature allows Mega Garchomp to hit hard with boosted Attack and take advantage of Trick Room with lowered Speed. Earthquake is a powerful STAB move that hits both foes, and Ground attacks have fantastic coverage. Dragon Claw allows Garchomp to hit opposing Dragons and other Pokemon that may resist his other attacks. Poison Jab is for Fairy types that threaten it and Grass types that resist Earthquake. Protect shields him for a turn and allows an ally to use a move that may hit it as well (Surf, for example) safely. It also allows the ally to switch out or eliminate a threat.
Garchomp with Metagross work really well together, with Garchomp dealing with Fire types and Metagross dealing with Fairy and Ice types. Garchomp also makes a good partner for Vikavolt, as Vikavolt is free to spam Discharge without worrying about the ally and Garchomp dealing with any of the Rock and Fire types that threaten it.
Metagross:
Metagross @ Assault Vest
Ability: Clear Body
EVs: 252 HP / 252 Atk / 4 Def
Adamant Nature
IVs: 0 Spe
- Meteor Mash
- Bullet Punch
- Zen Headbutt
- Hammer Arm
Metagross is a bulky attacker who can deal a lot of the types, like Rock, Fairy, and Ice types that may threaten its teammates. Assault Vest ensures bulkiness and Clear Body makes it unaffected by Intimidate, especially with Pokemon like Incineroar and Landorus-T and Mega Manectric running around. 252 HP and 4 Def make Metagross extremely bulky, and 252 Attack with an Adamant nature make Metagross stronger. The reason I have both Meteor Mash and Bullet Punch on the same Pokemon. Meteor Mash is a stronger Steel move and has a chance to increase the user's Attack. Bullet Punch is for finishing off Pokemon or revenge killing. It's also for priority, which is especially important in the case that the Trick Room setter goes down. It's also 100% accurate, so it can be very useful if I cannot risk missing. Zen Headbutt is for Psychic STAB, coverage, and flinching, and Hammer Arm can hit Dark types and other Steel types. Hammer Arm also lowers speed for Metagross, which is useful in taking full advantage of Trick Room.
Vikavolt and Metagross pair well together, since Metagross takes care of Rock types and Vikavolt can take care of Dark types that threaten Metagross and Water types Metagross may have trouble dealing with. Vikavolt may also deal with Ground types using HP Ice. Metagross and Porygon 2 work well together as well, as Metagross removes Fighting types and Porygon 2 uses Ice Beam to deal with Ground threats.
Vikavolt:
Vikavolt @ Choice Specs
Ability: Levitate
EVs: 252 HP / 252 SpA / 4 SpD
Quiet Nature
IVs: 0 Spe
- Bug Buzz
- Discharge
- Flash Cannon
- Hidden Power Ice
Vikavolt is a pretty powerful Pokemon with an amazing Special Attack, but it's brought down by its awful Speed. However, this is perfect for a Trick Room team. Choice Specs combined with a Quiet nature and maximum SpA EV investment increases Vikavolt's power. It also has maxed out HP and 4 SpD EVs for extra bulk. Bug Buzz and Discharge are STAB moves that are strong and reliable, and Tapu Fini can use Protect when it comes to Discharge. Flash Cannon can hit Gigalith and Alolan Ninetales. It can also hit Fairy types for Garchomp, who is probably the best partner for it. Hidden Power Ice is also good for dealing with Landorus-T, who otherwise completely walls Vikavolt.
Porygon 2:
Porygon2 @ Eviolite
Ability: Download
EVs: 244 HP / 76 Def / 188 SpD
IVs: 0 Spe
Sassy Nature
- Trick Room
- Ice Beam
- Thunderbolt
- Recover
This is the Trick Room setter of the team. Porygon 2's EVs ensure its bulk, and his bulk is increased by Eviolite. This EV spread and Sassy nature also allows it to survive Golduck's Hydro Vortex in the rain and a Scald from Pelipper depending on the Nature combination. The idea would be to survive the two attacks and set up Trick Room. It will also take less damage from Sandstorm or Burn damage. Download ensures that Porygon 2 can OHKO Garchomp (one without the assault vest) with Ice Beam if it gets a Special Attack boost. Ice Beam is used to attack Dragon types like Garchomp or Salamence or Landorus-T. Thunderbolt is used to hit Water and Flying types like Araquanid, Gyarados, Celesteela, which could use Porygon2 as a setup fodder or just knock it out. Recover is used to sponge strong attacks and Z-Moves and gives it the opportunity to set up Trick Room.
Porygon 2 appreciates Tapu Fini dealing with Fighting types and possible Dark types that may have Knock Off or Taunt, while in return it deals with Grass types by using Ice Beam and Water types with Thunderbolt that Tapu Fini may have trouble taking out. Porygon2 also deals with Water and Ground types for Arcanine, and Arcanine can weaken the opponents for Porygon2. Garchomp appreciates Porygon2 dealing with other Dragon types for it. Porygon2 is an absolutely essential teammate.