Gimmick Doubles Maison Team
I've had success with this team in the Maison in both X/Y and ORAS. This isn't a new (or groundbreaking) strategy but I thought I'd still share if anyone wants to try it out. It's a legitimate strategy, albeit gimmick-y, but can still pack a punch. I've also used it online occasionally with considerable success.
The team simply relies on Eruption spam under the sun. It's a decent team for farming BP in Super Doubles because you will most likely either win or get reasonably far.
Typhlosion @ Choice Scarf
(Blaze
or Flash Fire if you have it)
Timid
252 Speed, 252 SpA, 4 HP
Eruption
Extrasensory
HP Rock / HP Ground
Flamethrower
The destroyer and the core of the team. First turn: Eruption. Second turn: Eruption. Third: Eruption. Even Pokémon that resist fire (Water, Rock, other Fire Pokémon, etc.) will lose health considerably under the sun. Yes, you lose power when you lose HP, but nevertheless Eruption can still chip off a bit of damage. This is especially useful for Pokémon carrying a Focus Sash, slower than Scarfed Typhlosion, but are faster than Charizard Y. Flamethrower is there in case you've switch out Typhlosion (whose HP has dried up) and sun is still up. HP Ground/Rock for Flash Fire Pokémon.
The other moves rarely get usage unless you face threats (see below).
Charizard @ Charizardite Y
Doesn't Matter --> Drought
Timid
252 Speed, 252 SpA, 4 HP
Heat Wave
Solar Beam
Dragon Pulse
Air Cutter / Air Slash
The supporter. Main role is to set-up Drought for massive Eruption spam while Typhlosion is still at full health. Then, it can clean up opponents with Heat Wave. Solar Beam to finish off Water and/or Rock/Ground threats that have already lost considerable HP from sun-boosted Eruption. Dragon Pulse to finish off Dragons (which obviously resist fire) and everything else (hits neutral to everything that's not Fairy). Air Cutter has less power but hits both opponents for chipping off damage. Air Slash can be used in place of that for the very helpful flinch chance.
Greninja @ Expert Belt / Life Orb
Protean
Naive
252 Speed, 252 SpA, 4 Attack
Low Kick
Grass Knot
Ice Beam
Dark Pulse
When the AI leads with a threat that Typhlosion and Charizard-Y can't take down on their own, I bring him in to deal some damage. Low Kick for bulky heavy Pokémon (Tyranitar, Bastiodon, etc.), Grass Knot for bulky waters (Slowking mostly and those dual Water/Ground Pokémon). Ice Beam and Dark Pulse are just standard Greninja movesets.
I prefer Expert Belt only because Life Orb recoil turns me off.
Aerodactyl @ Focus Sash
Unnerve
Jolly
252 Speed, 252 Attack, 4 HP
Rock Slide
Wide Guard
Crunch
Aerial Ace / Earthquake
Aerodactyl's main role is to spam Rock Slide. Its secondary one is to use Wide Guard against incoming spread moves. Crunch is for Ghosts and Psychics that are likely going to use Trick Room (Hex Maniacs, Psychic AI). Aerial Ace is for evasion users. Sky Drop is also an option but I've had less success with that.
Unnerve is especially useful since most NPCs carry various berries.
OPTION
Metagross @ Metagrossite
Clear Body --> Tough Claws
Jolly
252 Speed, 252 Attack, 4 HP
Ice Punch
Protect
Bullet Punch
Brick Break / Earthquake (filler)
This one is an option if you can play with somebody. I used Metagross instead of Aerodactyl in my Super Multi run. Yes, Steven carries a Mega Metagross as well but truthfully, sometimes he makes questionable choices. So I opted to transfer Metagross to my other game and played with my other character locally.
Zen Headbutt may have STAB but I've missed a lot of times with it. I'm just unlucky.
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THREATS
Water Pokémon The three above earn special mentions due to them sporting strategies that disrupt my team's momentum. Slowking will most likely set-up Trick Room so it needs to be removed. Walrein can have Thick Fat and can hold a Quick Claw. Dewgong is also the same. Lanturn loves to paralyse with Thunder Wave. Typhlosion will almost always go first and at full health, it's going to put a dent on these pokés. Charizard can clean up afterwards. If two water Pokémon are in the field at the same time, take the lesser evil down.
Rock/Water Pokémon, like Barbaracle, Carracosta (with 4x fire resistance), as well as Water/Ground Pokémon like Swampert, Whiscash or Gastrodon can be eliminated with Solar Beam.
Rock Slide With this Eruption spam strategy, most Rock / Fighting pokémon you encounter will carry Rock Slide. If you can take them down with just Eruption and Heat Wave, do it; otherwise, switch out and bring in Aerodactyl. Aerodactyl isn't normally carrying Choice Scarf, so Typhlosion will outspeed it. On the rare occasions that they do, sorry but the chances of winning the match have greatly diminished. Lol. If you're using Mega Metagross instead, you can bring it in and use Bullet Punch. Archeops is also in the same vein but not as much as Aerodactyl.
Weather Setters One of the better aspects of Zard Y is that it can override any weather being initially set-up by the opponent once mega-evolved. The AI rarely uses manual sand but it does set-up Hail manually with Glaceon, Avalugg or Rain Dance with some frailer water types. Some NPCs have Sunny Day grass teams but that works to your advantage.
Fun fact: I've encountered a Snow Warning Aurorus that also set-up Sandstorm on the following turn. Lol.
Evasion We all hate to be on the opposing side if it. Double Team. Bright Powder. Lax Incense. If it's not your day, it can screw you. Other note-worthy threats are also those whose abilities help them evade. Watch out for Mismagius as well, it carries an evasion item sometimes.
Flash Fire Whenever I see the AI bring in a Pokémon that can potentially carry Flash Fire, I rethink strategy. Sometimes a risk pays off (in that they don't carry Flash Fire) but in other times, they don't. Sometimes I switch out Typhlosion and let Charizard do some damage. I bring in Aerodactyl to take them out. The AI rarely has two Flash Fire Pokémon out at the same time so you're good with using sun-boosted Heat Wave to take the other one out. Also watch out for Arcanine and Flash Fire Entei from some veterans.
Wide GuardSturdy Bastiodon is my #1 enemy and is the bane of my team. This is the most prominent Wide Guard user in Maison. On some occasions, you may also encounter Throh (rare) and Mienshao (even rarer) using this. For this reason, bring in Greninja to destroy it.
I shall copy it and make my doubles team in its image once I'm done with super singles.