Noivern V / Hoopa V
Arceus VSTAR accelerates energy on Hoopa V and Noivern V. Switch from Arceus VSTAR to Noivern V, use Copycat / Judge to attackt with Synchro Loud for 180 (210 with choice belt), then close the battle with Hoopa V's Shadow Impact for 170 (200 with choice belt) - (Mew and Urshifu VMAX decks are weak to Hoopa V!)
There are three ways you can find the pokemon you need to setup your bench:
Adventurer's Discovery, allows you to find three V pokemon (Basic, VMAX or VSTAR), which is great so you can quickly populate your bench or find Arceus V/VSTAR.
Quick/Ultra Ball, Not much to explain, just pick your discards wisely, energies or unneeded supporters/pokemon should be primary options. Also, these are the best options to find Lumineon or Manaphy if you need them quickly in your bench.
Stormy Mountains, has two jobs: find you basic dragon pokemon, so you can get Noivern V just in time, and also countering an opponent's stadium at the same time.
Both Noivern V and Hoopa V are squeeshy, meaning low HP count (200 and 220), you can use a Cape of Toughness on either one to bulky it up and resist a bit longer, combined with Crystal Cave to heal Noivern every time Hoopa attacks (30-30=0), and for Arceus, in case you desperately need it, find the Cheren's Care to heal all damage and recover it to your hand with all cards attached.
There are direct and indirect ways to help Noivern hit Synchro Loud every time:
Directly, Judge and Copycat supporters can guarantee it, but make sure you use them last in each round and avoid using any of the cards you draw or you will lose the damage boost. This can make the deck run slow, but retains sufficient timing to deliver high powered punches every round.
Indirectly, Marnie and Bird Keeper can help shape your hand when neither of the two direct options are available; Marnie drawing 5 cards for you and 4 for the opponent gives you a chance to play one last card before attacking which can be advantegeous depending on the situation; and Bird Keeper can sometimes add enough cards for you to match your opponent's hand and strike them back for a surprise KO.
The rest of the Trainer cards supply the deck with adapatability to different situations, mainly focused in switching and recovering position to ensure accelerating energy in the first rounds and mobility of the attackers to keep the pressure on the opponent. Among those cards you can use: Boss's Orders, Air Balloon, Escape Rope, Raihan and Switch.
Manaphy covers your bench from Urshifu VMAX RS; Lumineon can save the day by bring up a Judge in play or any Trainer card you may need at a moment's notice; Bibarel is the last engine piece with Industrious Incisors allowing you to keep your deck moving and at times helping you match your opponents hand to secure the Synchro Loud attack.
To ensure a more robust engine of the deck we would use Ordinary Rod to pull energies and pokemon from the discard pile into our deck. Allowing Adventurer's Discovery and Arceus VSTAR to search, find and put back into action those cards. Additionally, Pal Pad, can bring back to your deck Supporters you need again, such as Judge, Copycat, Marnie, Boss's Orders and Raihan, which can be drawn again using Lumineon.
There are variations for the deck that could give it a different dynamic within the same mechanic:
- Use four Copycat and remove the two Marnies. Increase consistency of Syncho Loud, but lose the ability to shake your opponent's hand and have an extra draw card to play before attacking.
- Remove one basic Dark energy and replace with a Capture Energy. Can speed up the setup process, but you may lack that last dark energy in the endgame.
- Find a way to include a line with a Cincinno with Make Do ability. In conjunction with Bibarel it could shape your hand just exactly how you need it to hit that Synchro Loud when missing a Judge or a Copycat, however there is not much space in the deck and in the bench or it. I wouldn't try it.
There are other potential replacements that can work but I haven't thought of. This build can be improved a lot, and if you find better cards to make it stronger, I would love to see your version. Thanks for reading all the way to here!