Nimble Innovator

The cantrip body, set at the rate that makes it filler rather than free. Four mana for a 2/2 that replaces itself is a known quantity going back to Coiling Oracle and the smaller relatives of Mulldrifter: you are not paying for the creature, you are paying for the card and accepting a warm body as the rounding error. The job here is curve-smoothing for a deck that wants bodies on the board without bleeding card advantage to put them there: the kind of effect a slow controlling shell leans on when its problem is running out of gas before its threats run out. The good versions of this template earn their keep with something extra (Mulldrifter flies and draws two, Sea Gate Oracle blocks from behind a sturdier toughness); this one carries no rider at all. It draws one, leaves a 2/2, and asks no further questions. That plainness is the point. It is a common-rarity load-bearing beam, the inclusion that never costs you a card to run, only tempo, and tempo is the cheapest thing a controlling blue deck has to spend.