These would be the cards corresponding to the free to play deck, initial pack 1 and initial pack 2. Remember that you can use a maximum of 3 cups of the same card in your deck.
You cannot add copies of cards that you do not have available
**If you go to the official KOD page and open the library, you can see the rest of the letter that the game contains. This will serve you for the last point of the contest.
Any questions you have about the contest do not hesitate to ask, you can find me on the official King Of Duels discord**