The deck of cards is documented under
Administration > Layout > System-Styles > Click "Action > Documentation" for Delos > Deck
There are different card sizes available
->withExtraSmallCardsSize()
->withSmallCardsSize()
->withNormalCardsSize()
->withLargeCardsSize()
->withExtraLargeCardsSize()
->withFullSizedCardsSize()
see also https://github.com/ILIAS-eLearning/ILIAS/blob/release_5-4/src/UI/Component/Deck/Deck.php