If you really want to play it, Juzm Djinn is a rather unremarkable 4-cost 5/5 beater, though it is worth mentioning that it was the first 4-cost 5/5
Portal Deck A and Deck B Uncut Sheets (Portal List and Alternate Text cards as well as 2 Black/Black Border filler cards are only on those sheets)
It reads, At the beginning of combat on your turn, equipped creature or a creature you control named Vecna gets +X/+X until end of turn, where X is the number of cards in your hand. Finally, The Book of Vile Darkness is a three mana Black Artifact that lets you create a 2/2 Zombie token if you lost two or more life in your turn
As with the other flashback cards on this list, Galvanic Iteration is commonly discarded or milled before being cast for its flashback cost as well
This is a no-brainer, but theres just no best booster to buy because it all depends on your need