There are fifteen cards plus a foil token in each Collector Booster found in eight "slots" in the booster. The slots are as follows:
• Two premium foil basic Nyx Lands—these are the full-art lands showcasing Nyx art. Every Collector Booster comes with two foil version lands. • Eight premium foil common, uncommon, or non-Nyx basic lands—there are 111 commons (including non-Nyx basic lands) and 80 uncommons in the set. Each booster will have eight cards from among those cards. • One ancillary card—each booster will contain one card from a Theros Beyond Death ancillary release, including Planeswalker Decks, Theme Boosters, and the Buy-a-Box promo. • One non-foil rare or mythic with the extended-art frame—similar to the Throne of Eldraine Collector Booster frames, these have extended art across the borders. • One premium foil rare or mythic rare—these can be either standard-frame or foil versions of the Collector Booster frame (point 4 above). • One non-foil Saga or constellation showcase-frame card—these can be uncommon, rare, or mythic rare and can include the borderless planeswalkers. • One foil constellation showcase-frame card—this slot will have one of the five uncommon showcase demigods, one of the six showcase rares, or one of the three borderless planeswalkers. • One premium foil double-sided token from Theros Beyond Death.