How are the cards determined in an incomplete deck of many things?

Question

In the description for the deck of many things magic item, there are two possible outcomes for how many cards are in the found deck:

Usually found in a box or pouch, this deck contains a number of cards made of ivory or vellum. Most (75 percent) of these decks have only thirteen cards, but the rest have twenty-two.

In the description for the magic item, there are 22 cards described. So if the deck is full, then every card on that description is in the deck. However, if the deck ends up only containing 13 cards, which cards are determined to be in this incomplete deck?

Answer 1

They are both preset decks

In the Deck of Many Things there are nine cards which are marked as only existing in the deck when there are all twenty-two cards, thus there are thirteen cards left and these are what make up the thirteen card deck, namely every King, Queen, and Jack and also the Joker (without TM):

• Ace of diamonds Vizier*
• King of diamonds Sun
• Queen of diamonds Moon
• Jack of diamonds Star
• Two of diamonds Comet*
• Ace of hearts The Fates*
• King of hearts Throne
• Queen of hearts Key
• Jack of hearts Knight
• Two of hearts Gem*
• Ace of clubs Talons*
• King of clubs The Void
• Queen of clubs Flames
• Jack of clubs Skull
• Two of clubs Idiot*
• Ace of spades Donjon*
• King of spades Ruin
• Queen of spades Euryale
• Jack of spades Rogue
• Two of spades Balance*
• Joker (with TM) Fool*
• Joker (without TM) Jester

*Found only in a deck with twenty-two cards