My doubles run just ended at 295 wins. A bit disappointed at the way I played in the final battle: I overlooked Sucker Punch from lead Mega Mawile and later let my Landorus die to a Dark Pulse unnecessarily. The 2 consecutive Quick Claw activations from Incineroar4 didn't help either.
Battle 296 vs. Punk Guy Etta: 4SUW-WWWW-WWW6-55XV
Still, I'm reasonably happy with this run, especially for a first attempt. This is actually my best run in doubles in any facility and I certainly wasn't expecting to get that far with this team. I might give this another shot in the future but for now this is what I have.
Team
Tapu Koko @ Choice Specs
Timid
Electric Surge
IVs: 31/1/31/31/31/31 (hyper trained)
EVs: 4/0/0/252/0/252
Thunderbolt
Dazzling Gleam
Grass Knot
Volt Switch
Fairly standard. Thunderbolt is the strongest move, but it's actually Volt Switch that gets the most mileage early in the battle. I prefer to let Tapu Koko leave the battle for a teammate after Electric Terrain is set as they tend to synergise better with Raichu type-wise. Thunderbolt sees more use later on when switching is no longer required but it will make an appearance during the first every now and again if I need to KO something dangerous right away (assuming Volt Switch isn't sufficient). Dazzling Gleam provides a secondary STAB and a spread damage move, and Grass Knot is only occasionally used for Ground-types although I'd prefer not to lock myself into it too early if I can help it.
Raichu-A @ Electrium-Z
Lonely
Surge Surfer
IVs: 31/31/31/31/31/31
EVs: 0/252/0/252/4/0
Volt Tackle
Psychic
Fake Out
Protect
The Tapu Koko + Raichu combo is well known. I found it to function similarly to Subway Politoed + Ludicolo in some ways, with Raichu acting in the Ludicolo role for Tapu Koko.
My Raichu is slightly different from other that have been posted here previously. Gigavolt Havoc has 190 base power when using Volt Tackle as the source move, and when you add STAB and Terrain boosts to that the power is pretty great. Volt Tackle itself is a strong STAB too, and the fact that it's a physical move adds a bit of variety to my lead combo as it compliments Tapu Koko's special offence. The downside is the recoil, which actually hasn't bothered me too much, Intimidate, and Volt Tackle's contact (but Gigavolt Havoc doesn't have contact which mitigates this somewhat).
Unfortunately, Raichu's physical movepool leaves a lot to be desired, so a mixed set with Psychic was in order. Raichu is fortunately fast enough to get away with this. Fake Out is essential for stage control and keeping threatening leads at bay. Last slot was a toss-up between Grass Knot and Protect. I opted for the latter and haven't looked back. Its most useful function is to counter greedy Sucker Punch spammers like Bisharp, but it also helps stall out Trick Room where necessary.
Raichu has 130 Speed with no investment, conveniently outspeeding Scarf Manectric in Terrain by 2 points. This allows full investment in Attack and Special Attack. Lonely was used as the nature since I couldn't use Adamant for obvious reasons, and Defense was the least salvageable defensive stat. The last 4 EVs go in Special Defense.
I think a similar set with Thunderbolt + Stoked Sparksurfer could be a reasonable replacement for this. I think I prefer the current set up but the alternative set would give Raichu guaranteed paralysis as well as the ability to invest more EVs into bulk. Intimidate would also be a non-issue. Food for thought.
Landorus @ Life Orb
Timid
Sheer Force
IVs: 31/10/30/31/31/31
EVs: 4/0/0/252/0/252
Earth Power
Sludge Bomb
Hidden Power [Ice]
Protect
I have always considered RNGing one of these and this team finally gave me an excuse to do so. Landorus is primarily helpful for its ability to deal with opposing Electric-types. The fact that Earth Power allows for this without harming my teammates is crucial for this team's success. Its immunity to Ground moves is another great reason to use Landorus as it gives me more options for deadling with incoming Ground moves and makes Landorus a decent Ground-type check. Sludge Bomb gives Landorus the ability to hit Fairy- and Grass-types and is actually not too bad as a back-up attack in its own right in situations where Earth Power is not appropriate. Hidden Power isn't used a lot but is useful for dealing with some Dragon-types and opposing Landorus/Gliscor. Protect is Protect. The moves can be altered to suit the team (Psychic and Grass Knot are other viable options) but overall this set up works for me. My only criticism of Landorus is that I wish it were just a bit faster, but it isn't difficult to work around this problem when everything else on the team is so fast.
Hawlucha @ Electric Seed
Adamant
Unburden
IVs: 31/31/31/x/31/31
EVs: 132/252/0/0/124/0
Acrobatics
Low Kick
Substitute
Tailwind
I'm rather proud of this set. I was worried that it would be too gimmicky and weak, but it exceeded my expectations and performed its role well.
There's a bit of a story behind how this came about. Initially I used a Mega Gyarados set (Jolly, Waterfall/Crunch/Ice Fang/Protect), based on
Pav A Nice Day's team, as I had a Jolly Gyarados stored among my collection and it seemed like a good way to get started. I ultimately found it to be a bit underwhelming, but most importantly I found my team lacks ways to deal with Grass-types efficiently. So I went back into my collection and came across a Tornadus with Acrobatics/Tailwind/Taunt/Substitute - a set I had used in the Subway as a Flying Gem lead to decent success. The unavailability of Flying Gem meant this Tornadus ended up rotting in storage throughout 6th gen, but with the introduction of Electric Surge and Electric Seed it had another opportunity to shine. Tornadus actually did pretty well, but I also found it a bit limited in coverage (only one STAB hurts it a bit I think). This is where Hawlucha comes in.
When Hawlucha switches into Terrain, Electric Seed is consumed (despite Flying-types otherwise ignoring Terrain). Aside from boosting Defense, this also grants a full power Acrobatics and activates Unburden, sending Hawlucha's Speed skyrocketing. Hawlucha's main purpose from there is to smash Grass-types, but the additional Fighting STAB expands its targets beyond what Tornadus could acheive. Being able to destroy Tyranitar (Chople Berry be damned) is particularly nice.
Substitute is used as a pseudo-Protect to bait and avoid attacks (knowing full well that baiting in general doesn't seem to be quite as reliable). It's a strategy inherited from Tornadus but Hawlucha is fast enough to pull it off too. The advantages of Substitute over Protect include the ability to use it multiple times consecutively without chance of fail (HP permitting) and the potential for prolonged protection if the Substitute survives the turn. One strategy I used every now and again was to throw out a sub while Hawlucha's teammate KOed one of the opposing Pokemon. In this situation, either sub is broken and a stronger hit is avoided, or I mispredict and the partner Pokemon is hit instead but the sub is undamaged and able to protect Hawlucha for subsequent turns. However, Substitute requires sufficient HP to be used and (unlike Tornadus with Prankster) it doesn't have priority and won't help a great deal when stalling Trick Room.
Tailwind is filler. I only added it because I knew I wouldn't be able to access it once I transferred Hawlucha from ORAS (necessary for Low Kick), but it was only used once to deal with an opposing Tailwind from Whimsicott4. It's expendable. Protect, Taunt, Ally Switch, or an additional coverage move could also be used as a replacement.
Hawlucha doesn't really need Speed investment due to Unburden, so after maxing Attack, the remaining EVs go into bulk. The spread doesn't mean a lot - it was the suggested spread from the maximizing your defenses app. However, this spread does make it marginally bulkier on both sides than an uninvested Tornadus, while also having more Speed with Unburden. The Attack drop is minimized by being able to use Adamant over Jolly, and the difference is ultimately small (and arguably canceled out by Hawlucha's additional STAB allowing it to cover more Pokemon).
As an aside, I think that the Terrain/Seed combo (whether it be with Hawlucha or Tornadus or something else) has some potential in other contexts that may be worth exploring, possibly with other Tapus. Might be something I'll look into in the future.
Threats
The following is not meant to be exhaustive, but does cover the main threats.
Trick Room is a problem for this team. I usually have to do everything in my power to stop it going up, whether it be with Fake Out or through simply powering through potential setters (double targeting is sometimes necessary on very bulky setters). If Trick Room does go up, smart switching and stalling with Protect are usually required to survive. This team has to approach Scientists with caution simply because of Trick Room.
I have to always be on the lookout for Lightning Rod opponents. Marowak2 can be irritating due to its Fake Out immunity, resistance to all of Tapu Koko's moves, and ability to smash Raichu with Shadow Bone. Rhyperior can also be tricky with a bad partner. Grass Knot is tempting but the possibility of Focus Sash encourages double targeting. But what if it's set 4 instead, and it uses Protect to nullify your attacks and give its partner free reign? Straight switching to both back-ups is often a decent strategy, although if it's paired with an Ice-type (most can be dealt with using Electric moves but this won't work in the presence of Lightning Rod) this becomes incredibly risky.
Some Electric-types with particular secondary traits that nullify Earth Power. Eelektross comes to mind immediately - set 3 can be rough due to its resilience and its access to super-effective coverage on Raichu. Some Rotom sets are also difficult. Rotom-Frost is the worst Rotom for this team due to its powerful Blizzard discouraging switching and the general difficulty in KOing it quickly with the leads. Rotom-Heat is slightly easier to switch into but additionally walls Tapu Koko. Rotom-Mow cares the least about my Electric moves but is vulnerable to Sludge Bomb at least. Rotom-Wash and Rotom-Fan are the easiest to deal with (Gigavolt Havoc works well enough).
As alluded to above, Ice-types discourage switching but many are easy enough to remove. One Ice-type that does make me nervous is Glaceon. Similar to Rhyperior, set 3 has Focus Sash to encourage double targeting but set 4 has Detect to punish this strategy. With a bad partner, dealing with it can be a gamble. I find Dazzling Gleam to be useful in these situations - if Glaceon does block with Detect then at least the partner will take some damage. I imagine Abomasnow would be another Ice-type that would be a pain for similar reasons (plus it has an Electric resistance) but I was fortunate not to have to face one throughout this streak.