Thraben Inspector

The cleanest replacement-level white one-drop ever printed, and the rare card where "replacement-level" is the compliment. A 1/2 body for one white mana is filler; the Clue token stapled to it converts that filler into a deferred cantrip, and that conversion is the reason the card is a default rather than a cut. You play a body now and hold the card-draw for a turn that can afford it, so the slot never feels wasted. That structure (immediate board presence plus a card stored in artifact form for later) is why it slots into nearly any white deck that wants bodies without bleeding cards: the floor is a real blocker, and the ceiling is two cards' worth of value across two turns. The Clue also does quiet work a flat cantrip cannot: it sits on the battlefield as an artifact, feeding improvise, affinity, artifact sacrifice, and any deck that counts permanents, so the same template that draws a card can also be fuel. Investigate as a mechanic has recurred often since this kind of design first appeared, but this is the cheapest, most frictionless instance of it: no enters-the-battlefield drawback, no conditional trigger, no relevant downside. It asks nothing and gives a small, guaranteed return, which is exactly the profile that carries a card from playable to omnipresent.