However, like a jihad, a crusade has a second meaning: "to lead or take part in an energetic and organized campaign concerning a social, political, or religious issue." In this sense, Crusade like Jihad has an entire definition removing it from the violence of the Middle Ages
You can do the math quickly30 Premium Helvaults, 54 foil oversized cards in each
Wizards Rockets Wizard's Rockets has the downside of not being able to be used right away, but you can sacrifice it through other effects like the bargain mechanic or Deadly Dispute
The much more unlikely possibility is the return of battle cards, but it would fit the theming if handled right
They represent some potentially really powerful interactions when you look at formats with Stoneforge Mystic in, because the mystic allows you to fetch up equipment cards from your deck and even put them into play for a low cost