In each 12-card booster, you'll find:
- 1 Mystical Archive card (uncommon, rare, or mythic rare)
- 1 Lesson card of any rarity
- 1 Traditional foil card of any rarity*
- 1 Card from The List in 1 out of 4 boosters
(*This includes global Mystical Archive cards in all non-Japanese Set Boosters, and both global and Japanese alternate-art Mystical Archive cards in Japanese Set Boosters.)
Plus, you get a delightful art card, 1 in 20 of which feature a foil-stamped logo or artist signature! There may be a couple of terms you are unfamiliar with here, but this reading assignment should elucidate the matter.