Secret Pack - Yugipedia - Yu-Gi-Oh! wiki

A Secret Pack is a type of card pack in the game Yu-Gi-Oh! Master Duel. These packs are based around a theme, which is typically 1 or more archetypes, and pull from a featured card pool of 40 or fewer cards to help build a Deck based around that theme, in addition to several cards from the Master Pack. Secret Packs serve as the main way to obtain cards for a specific Deck.

25th Anniversary Tin: Dueling Heroes Mega Pack - Yugipedia - Yu-Gi-Oh! wiki

Purrely (archetype), Yu-Gi-Oh! Wiki

Ten Thousand Dragon - Yugipedia - Yu-Gi-Oh! wiki in 2023

Ishizu Ishtar, Yu-Gi-Oh! Wiki

Yu-Gi-Oh! Master Duel, Yu-Gi-Oh! Wiki

Metal Raiders, Yu-Gi-Oh! Wiki

Legendary Collection: 25th Anniversary Edition, Yu-Gi-Oh! Wiki

Cross-Dimensional Contracts - Yugipedia - Yu-Gi-Oh! wiki

Gargantuan Gears - Yugipedia - Yu-Gi-Oh! wiki