Streets of New Capenna Set Boosters always contain a card with the golden age or skyscraper treatment, a traditional foil card, and an art card. Four percent of Set Boosters contain a gilded card. The commons and uncommons in a specific Set Booster are connected, telling little stories about the families of New Capenna. Finally, there's always the chance of opening a card on The List (including Magic-themed versions of cards from Stranger Things x Secret Lair).
Starting with Innistrad: Midnight Hunt, Wizards of the Coast have been including several Commander cards in Set Boosters. In addition to the ten legendary creature "face" cards from Streets of New Capenna Commander decks, you can find eight more new-to-Magic Commander cards that aren't found in those Commander decks.