Ive mentioned cards and damage as a resource, but theres also Time to be seen as a resource
basic rules of combat that has a major impact on how and when you activate effects during battles
Early Upper Deck booster packs contained a random assortment of nine cards (rarity and value varied), with the whole set ranging around one hundred and thirty cards, as to catch up with the Japanese card pool, two or more original sets were combined into one
The Rose Cards being fought over by the Lancastrians and Yorkists are also spoken of in Druid legends, with Seto referring to the Red Rose Cards as "Celtic Red Rose cards" when he first appears at Stonehenge, though Rosenkreuz claims there's quite a bit of embellishment about these cards in the Druids' account
Excellent inclusion in many decks, especially: 1 Frog Decks (great tribute fodder for him constantly generated) 2 Zombies (DARK synergy, good level for Synchros, decent tribute fodder generation) 3 Aggro decks 4 TeleDAD and Vayu Turbo (also good for same reasons as Zombies) 5 Decks that are generally good at keeping monsters on field or generating fodder