Narset, Jeskai Waymaster

Every wheel effect before this one asked you to empty a hand you were done with; this one asks you to have spent the turn first. The end-step trigger reads your spell count, so the refill is only as good as the tempo you generated to earn it: cast nothing and discarding your hand is pure downside, but chain a couple of cheap spells and you convert a spent grip into a fresh handful going into your opponents' turn. That reordering is the whole design. It rewards the low-curve, spell-dense Jeskai game plan that wants to keep casting rather than sit on cards, and it gives nothing to a passive turn. Sturdy enough to weather the incidental burn and small ping effects that would otherwise strand the trigger, it survives on a board where a more fragile monk would already be dead, so the engine actually gets to fire. Note too that the discard and the draw happen within a single trigger resolved at the end step, so you refill before you pass, rather than casting out your whole grip and handing the opponent a turn against an empty hand. As a Narset, the card keeps the through-line of the name, a spell-obsessed Jeskai mind whose past incarnations have exiled-and-cast and taken extra turns; but the mechanic here is its own idea: a wheel with a throttle, priced to the work you did before you pulled it.