the agent deck yugioh Yu-Gi-Oh! - of Mystery - Earth (SDLS-EN002) - Structure Deck: Lost Sanctuary - 1st Edition Suppressive The Agent Deck 2019

If your opponent cant get rid of it when you summon it

"Runick" features no main deck monsters, instead deciding to focus on a flurry of spell cards that each mill a specified amount of cards from the opponent's deck to the GY

Battle Pack lets you buy random packs and use what you pull to make decks

When your opponent activates a card or effect: Negate the activation, and if you do, destroy that card

Its a natural fit for red aggressive or midrange decks that want to apply pressure without committing to a full lock

(There was a time when there was no maximum limit, which swiftly changed after someone entered a German tournament with a 2000+ card deck.) A tournament deck will always be 40 cards because the fewer cards you have, the more likely you are to draw the ones you want