The vault's ultimate prize wasn't exactly what Kellan had imagined
In fact, with Dionus in the command zone you can actually include a +1/+1 Counter sub-theme, which is incredibly useful to Elfball in particular as it helps shore up traditional weaknesses to the archetype: Elves a vulnerable to board wipes, so adding extra draw and protection like Inspiring Call and Armorcraft Judge make it far easier to avoid getting shut down by wipes
Sazh himself can call up a vital land or Bird card, while Bartz can make your flock gang up on a particular enemy when he enters
Sleeving protects a cards edges from wear, its faces from scuffing during play or handling, and protects it from any liquid or dust that could damage it
On the opposite end of this spectrum are the types that only show up on very rare occasions, have rarely been focused on in a set, and have less cohesive themes
Nevertheless, this heavy play has resulted in it making itself quite pricey on the market