It is a game rule that you must have at least 1 Basic Pokmon in your deck
It's the sort of thing you can do to win the game or, at least, put you so far ahead there isn't much anyone can do about it

Checkout Navigation Nerd Rage Gaming Back to Mystery Booster 2 Lightly Played, English, 2 In stock Details Color: White Rarity: R Cost: 2WW Card Type: Sorcery Artist: Vincent Proce Name: Day of Judgment Finish: Regular Card Number: 0008 Set Name: Mystery Booster 2 Category: Mystery Booster 2 Related Products Day of Judgment Foundations Lightly Played, English 1 In Stock Lightly Played, English 1 In Stock Lightly Played, English 1 In Stock NRG Exclusive - NM, English 5 In Stock Day of Judgment Magic 2012 (M12) Lightly Played, English 1 In Stock Lightly Played, English 1 In Stock Lightly Played, English 1 In Stock Day of Judgment Zendikar Moderately Played, English 1 In Stock Moderately Played, English 1 In Stock Moderately Played, English 1 In Stock Soul of Theros (White Border) Mystery Booster 2 Near Mint, English 1 In Stock Near Mint, English 1 In Stock Near Mint, English 1 In Stock King's Assassin (White Border) Mystery Booster 2 Near Mint, English 1 In Stock Near Mint, English 1 In Stock Near Mint, English 1 In Stock Cunning Wish (Future Sight) Mystery Booster 2 NRG Exclusive - NM, English 1 In Stock NRG Exclusive - NM, English 1 In Stock NRG Exclusive - NM, English 1 In Stock Snow-Covered Plains (White Border) Mystery Booster 2 Near Mint, English 4 In Stock Near Mint, English 4 In Stock Near Mint, English 4 In Stock Mardu Outrider (White Border) Mystery Booster 2 Near Mint, English 4 In Stock Near Mint, English 4 In Stock Near Mint, English 4 In Stock

The deck supports this through a number of cards with high toughness (walls, etc) that are also strong defensive bodies
A first thought to take advantage of this ability would be the Mill ability to move creature cards directly from the deck to the graveyard
So until next time, may your holiday season be full of drafts and sealed decks!