Elite Trainer Box

In more detail

Bulbapedia, a fan wiki, says the first Elite Trainer Box came with the Plasma Storm expansion and that nearly every expansion since has had one, and it lists the standard box from Scarlet & Violet on as holding 9 booster packs and a promo card. For the Pitch Black expansion, the Pokémon TCG site lists 9 packs, a full art foil promo card, 65 card sleeves, 40 Energy cards and a box with 6 dividers, among other items.

The Pokémon Center Elite Trainer Box is a premium version sold through Pokémon Center, which Bulbapedia says was first made for Chilling Reign. From Scarlet & Violet on, Bulbapedia lists it with 11 packs and a second promo card stamped for Pokémon Center, and the Pokémon TCG site shows the Pitch Black version with 11 packs and a second promo card carrying a Pokémon Center logo. Bulbapedia adds that Elite Trainer Boxes have no Japanese equivalent.

Some expansions get two boxes with different themes, which hold the same packs but different sleeves, dividers and promos. Check which version a listing offers, and treat the box as sealed product: the wrap should be intact before you pay a sealed price.