From Bulbapedia, the community-driven Pokémon encyclopedia.
The Fire Deck is a theme Half Deck from Pokémon Play It!. It predominantly focuses on -type Pokémon.
In Pokémon Play It!, it is one of four decks available for the player. Julie always uses the Fighting Deck against it. She never uses the deck herself.
In Pokémon Play It! Version 2, this deck appears on the third "Basic Challenge" level, which is a Fire vs. Fighting duel.