Trading cards and gaming cards (such as those from collector card games) are protected from damage and stored using card binders and 9-pocket sheets. A 3-ring binder or a D-ring binder is frequently used with card binders.
A 3×3 plastic page with 9 pockets, also known as a 9-card page or a 9-card sleeve, holds 3 cards per row and 3 cards per column. There are other varieties of this card pocket page type.
Additionally, some collectors choose not to place multiple cards in a pocket as opposed to placing duplicates all in the same pocket (known as a “double up”) or inserting cards backwards to be presented on the opposite side of the page.
Since the acid in the plastic sleeves can harm your cards, a binder with such sleeves is a significant benefit. Most collectors advise using a D-ring fixed-page binder to prevent any damage.
Trading cards are rumored to flex easily in O-ring binders. Binders with side-loading compartments are also recommended by knowledgeable trading card collectors.
Pokémon binders: What is Pokémon binders?
Pokemon Card Holder Book, Compatible with Pokémon Trading Cards, Holds Up to 400 Cards, 50 Pieces 4-Pocket Pages, Card Collector Album with Zipper Carrying Case, Binder for Pokemon Cards with Sleeves