how many pokemon cards are in a deck Learn to Build Pokémon TCG Pocket Pokemon TCG - Choose Your
Description
For a deck that is mono-colored or is only one type of mana, players normally can take out an additional basic mana card, preferably not going below 20 mana to avoid becoming mana starved

You're not getting a card in a plain envelope
While these Halloween sets have always contained reprinted cards, the description for this year may be indicating the set will feature exclusive cards
Since it might be your first-time, my recommendation is just play and have a good time
