Decklist from LittleRiver.
This deck uses the unlikely pairing of Claydol and Sceptile ex δ. Claydol is your early-game hitter, with an efficient attack and a Poké-Power that helps set up. Sceptile ex δ slows down opposing ex decks and comes in much later, when your opponent has taken enough Prizes to boost Power Revenge.
Lead with Baltoy, evolve to Claydol as soon as possible, and use Psychic Trace to set up. At the same time, attach Energy onto it and use Ancient Mantra to pile damage and Confusion on your opponent's board.
Jirachi is there if you need to take things a little slower and not rush into taking Prizes. Castaway pairs well with it, since you can search for Fluffy Berry to get your Active out, as well as an Energy for its Make a Wish attack.
Alakazam ☆ is also there if you need to slow down. It's basically Minun with more HP; Psychic Select lets you reuse resources, so you can loop Pow, or eventually get a disruptive Stadium to stick through all your opponent's Windstorms, or loop Mr. Stone's Project against Energy denial decks. In a pinch, you can get three Energy onto it and use Skill Copy, discarding Sceptile ex δ for Power Revenge.
Get Sceptile ex δ down if your opponent is disrupted by Extra Liquid. Attach Energy to it slowly over the course of the game and use it to take the last few Prizes, when Power Revenge's damage output is at its highest. Use Roselia to chip opposing Pokémon into Power Revenge 1HKO range if possible.
This deck uses 2 Holon Adventurer instead of the usual 1-1 Adventurer/Scientist split. Psychic Trace already matches your opponent's hand size, so Scientist is less useful.
Mr. Stone's Project is not commonly played, but I feel it fits this deck. Usually you would play Holon Farmer for this sort of Energy-recycling effect, but Mr. Stone's Project is useful even early-game to help meet Ancient Mantra's color requirements. It's also better against Numel's Kindle since the Energy goes to hand for immediate re-attachment.
I use a 2-2-2 Sceptile ex δ line with Jirachi, LittleRiver uses 3-1-3 with Rare Candies. I prefer Jirachi since there's only one Stage 2 line (and no Lunatone to search for Rare Candy), and with Jirachi around, having 2 Grovyle is pretty much necessary to avoid Prizing all copies and having none left in the deck to Make a Wish for. Grovyle is also relevant against Latios ex δ — Latios hits Claydol for Weakness, and the Sceptile line resists it, but Sceptile ex is still an ex and walled by Ice Barrier. Having Grovyle means you can actually damage it. (Even Jirachi can hit it for double damage if you attach Psychic + Multi Energy!)
This deck isn't widely played, so this section is just going to be about the differences between LittleRiver's list and mine.
Holon Farmer: over Mr. Stone's Project. Searchable with Holon Transceiver.
3-1-3 Sceptile ex δ + 3 Rare Candy: over 2-2-2 and Jirachi.
2-2 Dugtrio: can help chip with Dig Under to bring things into Power Revenge 1HKO range.
Lapras + Swoop! Teleporter: consistency.
Claydol and Sceptile ex δ cover each other's weaknesses extremely well. Claydol is weak to Water, which the Sceptile line not only resists, but also hits for Weakness against (Mew ☆ δ, Latios ex δ). Claydol is soft to Cessation Crystal shutting down Psychic Trace; against that, Sceptile ex δ can come in and attack with Power Revenge for only 2 Energy, since Crystal turns off Extra Liquid. Claydol hits Darkness-types that resist Psychic (Dark Tyranitar, Rocket's Sneasel ex) for Weakness.
Claydol can get walled by Fighting Resistance. You do have Sceptile ex δ as an alternative attacker, but it's not easy to power up early in the game. Crystal Shard and Magnetic Storm can get around Resistance, but are easily removed.
Arcanine ex is a bad matchup. It hits the Sceptile line for Weakness, and Confusion from Ancient Mantra is easily cleared by Fire Remedy. One Overrun will KO Jirachi after it's taken 10 damage from Make a Wish. Tech Safeguard Wobbuffet or Celebi ex to improve this.