Unlimited Decklists and Discussion #1: Porydonk

Porydonk (XY rules change)

Pokémon: 17

2-2 Porygon2 (Great Encounters)

2-2-2 Shiftry (Next Destinies)

2 Uxie (Legends Awakened)

1 Azelf (Legends Awakened)

4 Sableye (Stormfront)

Trainers: 43

4 Erika (Gym Heroes)

4 Scoop Up (Base Set)

4 Item Finder (Base Set)

4 Junk Arm (HS Triumphant)

4 Level Ball (Next Destinies)

4 Poké Drawer + (Stormfront)

4 Seeker (HS Triumphant)

4 Devolution Spray (Dragons Exalted)

3 Broken Time-Space (Platinum)

2 Professor Oak (Base Set)

1 Luxury Ball (Stormfront)

1 VS Seeker (ex FireRed Leaf Green)

1 Oracle (Skyridge)

1 Pokédex Handy910is (Diamond & Pearl)

1 Computer Search (Boundaries Crossed)

1 Pokémon Retriever (ex Team Rocket Returns)

My updated Porydonk list. Previously, Drifblim (HS Undaunted) was used to shuffle the Defending Pokémon back into your opponent's deck, but it has been replaced by Shiftry since the XY rules change took effect (whoever goes first cannot attack). This makes the deck slightly less consistent than before since it requires a Stage 2 evolution line and a full playset of Devolution Spray (thus increasing the number of dead draws); additionally, even when fully setup, there's a small chance to lose to bad luck with coin flips. On the plus side, using an Ability to win the game bypasses annoying Poké-Bodies such as Toxicroak G's (Platinum).

The deck plays very much the same as before: repeatedly use Erika and Uxie to draw through your deck, play a Broken Time-Space and evolve a Benched Porygon to Porygon2. Use the latter's Poké-Power to discard Seeker, forcing your opponent to return a Benched Pokémon to their hand, while you return Porygon2 and replay it. Rinse and repeat until your opponent has no Bench, then set up a Shiftry and use its Ability to shuffle their last Pokémon into their deck for the win. Devolution Spray is used to replay Shiftry and use Giant Fan again.

A few less obvious observations to keep in mind:

-When you discard Seeker to Download in order to return your opponent's last Benched Pokémon to their hand, you don't actually need to return Porygon2 again. Instead, you can return an Uxie for additional draw power, or even a Shiftry if you had to evolve it before.

-Expanding on the previous note: sometimes, you may be forced to play Shiftry before getting rid of your opponent's Bench (e.g. if you have a Nuzleaf in play, Shiftry in hand and need to play Professor Oak). While not optional (this means you'll have one less shot at winning the game later), this is not entirely problematic; you can return Shiftry to your hand later, when using the last Seeker, and replay it. In this case, if you hit heads the first time with Giant Fan, you will have essentially used Shiftry as a Seeker, and vice-versa.

-You may be forced to return an Uxie to your hand with Download instead of Porygon2 in order to keep drawing cards. This means that you will be unable to use Download again. There are a few ways around this: the most obvious one is just playing another Porygon2, but you can also use a Devolution Spray and replay the original Porygon2, or even Scoop Up the Porygon and recover the discarded Stage 1 with Pokémon Retriever.