Gardevoir ex (Destined Rivals)

This deck literally keeps getting stronger and stronger.

Strategy: So, I would recommend going second with this deck as you can use TM: Evolution to get out your Kirlia's which makes getting Gardy much more effecienly. Though, if you end up going first that's not too bad there are still things you can do. Now for your First Turn, try to get as many Psychic Energies you can into your Discard Pile, this will be REALLY helpful later on into the game. Also, do note that this deck plays fairly slow. Furthermore,

This deck literally keeps getting stronger and stronger.

Strategy: So, I would recommend going second with this deck as you can use TM: Evolution to get out your Kirlia's which makes getting Gardy much more effecienly. Though, if you end up going first that's not too bad there are still things you can do. Now for your First Turn, try to get as many Psychic Energies you can into your Discard Pile, this will be REALLY helpful later on into the game. Also, do note that this deck plays fairly slow. Furthermore, do attempt to get out 2 Ralts, Munkidori, Mew ex (Debatable as you can draw more cards at times with it), and Shaymin if you're playing against a deck that has Snipe Attacks like Wellspring Ogerpon or Blaziken from Destined Rivals. You can also get out Drifloon or Scream Tail but I personally like to keep them hidden until later on into the game. Anyways, you should also try to get out Gardevoir ex as soon as you can due to the Ability Psychic Embrace essentially being your deck's Engine. Munkidori is preferably at 3 Copies as it also lowers your Mulligans from happening as often and to ensure you get at least 1 Munkidori into play. Now I'll cover the purpose of why Klefki was being played in this deck, Klefki's main purpose was to slow down your Opponent and can essentially let you win in certain matchups especially if you're going first, Mischevous Lock shuts down all Basic Pokémon's Abilities as long it's in the Active which can shut off Miraidon's Tandem Unit in Joltik Box which makes that tough matchup a bit easier. Also, since Pult was once the BDIF, Clef gives a Weakness to Pult and Raging Bt essentially making those matchups a lot easier with your Attackers. Full Moon Rondo could be used as well which will be quite helpful since you may fill up your bench quite a bit along with your Opponent. Mew ex does mainly function for Draw Support but it also allows you to use Genome Hacking which can copy one of your Opponent's Active Pokémon's Attacks which could potentially do something like hitting Pult for 400 due to the Weakness from Clef and spread Damage onto them further. Munkidori also does heal your Pokémon like Gardy and moves it onto your Opponent's which is really helpful and Mind Bend is a great Attack early on. Now your main Attackers, Scream Tail and Drifloon, by getting Psychic Energies into the discard pile, Psychic Embrace can get those Energies into your Attackers and damage them in the process which furthers your damage output. Scream Tail is your Sniper Attacker though it does get blocked by cards like Shaymin, and Drifloon is just a strong Attacker overall. Their HP can go further to alllow more damage onto them thanks to Bravery Charm, and Shaymin protects your Bench a bit earlier on which is really helpful especially when setting up. Now for the ACE SPEC of choice, Secret Box, this is arguably the best choice in Gardy as you can get out a Stadium, Supporter, Item, and Tool Card. Well that's all for the strategy so feel free to make any changes or to leave any suggestions!

Matchups:

Now I won't be covering many matchups like I did for Joltik Box, but I will still do the more common decks you'll face against.

Pult: This is pretty straightforward, try to take second from them, get out Lillie's Clefairy ex, get set up and then annihilate Pult. Though, Phantom Dive is quite annoying and things still could go south and go in their favor so still be careful.

Zard: Zard hits you for weakness, this deck may be less common but it has been doing better in Destined Rivals due to Shaymin but you should be really careful against this deck as one wrong move can make them win. You should try to get Drifloon to swing for high damage and do be careful with Gardy as if they boss it up, Gardy can be OHKO'd. Also, Clef doesn't really do much here.

Gholdengo: Alright, so try taking second from them so they can't use TM: Evo, Clef counters the Pult build but still gets hit by Weakness from Gholdengo so be careful if you're against the Pult Build, try to build up your Drifloon or Scream Tail so they can do high damage. This is a bit off a tough matchup and the Dudunsparce Build, I don't really have anything to say for that.

Joltik Box: This is arguably your toughest matchup. Try to take second from them to prevent Joltik from using Jolting Charge. Try to KO Hands as soon as you can since that's the main threat to this deck, Pikachu is a bit scary but the Spread from Munkidori can ruin Resolute Heart. You need to get out your Attackers prepared as soon as you can.

Raging Bolt: Pretty odd matchup but try to prevent Bolt from getting set up if possible and if they get Noctowl in hand from Fan Rotom, use Iono if you have it in hand to prevent them from getting the cards that they need.

TeraBox: This deck fell off in Destined Rivals because of Shaymin stopping the Snipe Attack from Wellspring. Anyways, as per usual, go second and start setting up as you usually do. Use Munkidori to ruin Pika's Resolute Heart and Cornerstone isn't really a threat since your Attackers have no Abilities. Clef is a decent attacker since they'll fill up their bench a lot. So this matchup is quite a bit in your favor also get Shaymin out to stop Wellspring Ogerpon.

N's Zoroark: This deck is a bit unfavorable since Zoroark hits your Pokémon for weakness. Try to get rid of their Benched N's Pokémon to neutralize Night Joker, Iono can also be quite helpful as the disruption is excellent against their Draw Engine since they have to discard a card from hand and draw 2 which does kind of Mill themselves further. Clef is a decent Attacker, be careful with Mew, and Shaymin is nice to use against the Darmanitan's Snipe Attack. Do also bump their N's Castle whenever you can.

Archaludon: This is quite an odd matchup as I haven't played too many Archaludon decks with Gardy. The Poison later on can be quite threatening especially to your Attackers Scream Tail and Drifloon so be REALLY careful against that. Though, if they're playing the Hop's Zacian Build, get Shaymin to stop the snipe from Insta-Strike, Munkidori is quite helpful in both matchups and DO NOT get out Clef in either builds, you're giving up free prizes with it.

Roaring Moon: Same as Archaludon, they may Donk you,  Your Pokémon are weak to Moon though so be really careful. Keeping Gardy alive is really essential into winning and be really careful with your Attackers Drifloon and Scream Tail. Munkidori can help move your damage onto their Pokémon. Overall, this is a bit of a tough matchup.

Marnie's Grimmsnarl: Their Froslass doesn't really do much but Grimmsnarl is quite the threat with its spread damage and their Munkidori's make it worse, you desperately need to get set up as soon as possible, you need to take out their Impidimp's and Mogrem's whenever possible, Shaymin is good as it blocks the 30 Damage Snipe from Grimmsnarl but it still takes damage from Froslass if they play it on the field. Be really cautious in this matchup, this is one of your more difficult one's as well.

CTC: There are many great cards that could be added so I'll give a list of them and a brief explanation.

- 1 Moonlit Hill - Helps heal your Pokémon Slightly and makes you discard a Psychic Energy.

- 1 Lively Stadium - Increases the total HP of your Basic Pokémon which can further Scream Tail and Drifloon's damage output but also does increase your Opponent's. It's basically a Double-Edged Sword.

- 1-2 Team Rocket's Ventute Bomb which combo's with Munkidori as if you flip Tails, use Adrena-Brain and regardless forces damage onto your Opponent.

- 1 Klefki - Helps in your Joltik Box matchup especially when you're forced to go first.

- 1-2 N's Zorua and 2 N's Zoroark - Good Draw Support and does the same as what refinement Kirlia did but it is kind of risky but overall a good Tech Card.

- 1 Flutter Mane - An alternative to Klefki but gets rid of the Ability of only the Active Pokémon of your Oponnent's.

- 1 Cleffa - Provides early game draw support with Grasping Draw.

- 1 Budew - Itchy Pollen provides Early Game stall when you slowly set up.

- 4 Arven's - Helps search your deck for item and tool cards which is really helpful.

- 1 Boss's Orders - Good Gusting option, especially if you used your Counter Catchers already.

- 2 Morty's Conviction - Another good Tech Card used as Draw Support.

- 1 Turo's Scenario - Resets your Gardy and removes all damage from it and it also does get the Psychic Energy into your Discard Pile. I'd recommend using this card if you run N's Zoroark.

- Unfair Stamp - An alternative ACE SPEC choice, it's really great at disrupting but Secret Box is generally better.

- Brilliant Blender - Another alternative choice as it gets your Psychic Energy into the Discard Pile instantly, I'd recommend this as a second choice if you don't own Secret Box and it's a bit easier to use if you're still new to PTCG.

Edits:

Edit #1: Cut an Ultra Ball for TM: Evolution. This change happened as I made an error in adding 4 Ultra Ball's instead of 3 since I also noticed TM: Evo was missing.

Edit #2: Cut 2 Stretcher's, 1 Iono, 4 Nest Ball's, and 1 Rare Candy. They've been replaced with 4 Arven's, a 3rd Bravery Charm, and a 2nd TM: Evolution. These changes were needed in making this deck a lot better.

Edit #2.5: Reverted most of the changes from Edit #2 and added in Cleffa and the removal of both TM: Evo's and Klefki.

Edit #3: Modified some of the description and made this list up to date for the current state of the Destined Rivals format. 2 Arven's, 1 Buddy-Buddy Poffin, 2 TM: Evolution's, 4th Ultra Ball, and 1 Super Rod were all added to make this list much stronger in this format but it came at the cost of 2 Nest Ball's, 2 Night Stretcher's, 1 Cleffa, 1 Budew, and 1 Bravery Charm. I am still trying to find a card to cut in order to keep Budew in so in Edit #4 (If it does release) should have Budew in it.