From Bulbapedia, the community-driven Pokémon encyclopedia.
The Barrier Swap Deck is a type deck found in the Gym Heroes Strategy Guide. The deck is classified as one of the advanced decks, containing more rare cards and strategy than other easy-to-build decks.
The "Barrier Swap" deck has a truly fantastic combo in Alakazam and Erika's Dratini. Get Alakazam onto your Bench, and make Erika's Dratini your Active Pokémon. Now you can use Dratini's Pokémon Power: Strange Barrier to make sure Dratini only takes 10 damage a turn and then move that damage onto another Pokémon using Alakazam's Pokémon Power: Damage Swap.
If you move the damage onto Chansey, you can then use Scoop Up when Chansey gets close to being Knocked Out. Then you can put Chansey back on your Bench, and it's ready to take some more damage. Use the Full Heal Trainer card or Full heal Energy on Dratini if your opponent uses any special attacks on it. Pokémon Trader and Pokémon Breeder, along with card drawing cards like Bill and Professor Oak, should get you all the Pokémon you need as quickly as possible.