one piece four emperors booster box Luffy and Buggy finally appear alongside Shanks and teach as the new Four Emperors One Piece OP09 The Four

Ninjas with a low ninjutsu cost like Prosperous Thief and Ingenious Infiltrator can help you save mana for flashier game-ending spells like Kotose, the Silent Spider

Number Nine The ultimate, "Anything you can do, I can do better!" card

When Palinchron enters the battlefield, you get to untap up to seven lands, a nice little refund for casting this seven mana flyer

The Legend of Kuruk / Avatar Kuruk The Legend of Kuruk lets you Preordain twice before it becomes a finisher in Avatar Kuruk, which acts like a Young Pyromancer

Build a deck, play 3 rounds, get 2 packs for playing

As for spells, mana cost doesn't matter so much as function