From Bulbapedia, the community-driven Pokémon encyclopedia.
Practice Deck is a Theme Deck from Pokémon Card GB2: Here Comes Team GR! for the Game Boy Color. The deck is only used by the player when battling against Tech Sam at the Mason Laboratory. Due to it being used only in the practice battle against Sam, the cards are dealt the same way each time, and therefore some of the cards listed below may never appear during the duel. This is a different deck than the Practice Deck used in Pokémon Trading Card Game.
Whether playing a practice match or playing an actual dual with Tech Sam, the same deck build is used.