Elvish Mariner

Most scry payoffs pay you in card quality: this one converts the act of looking into a tap effect, turning a passive selection step into a board-affecting lever. The attack trigger is the small end of the deal, scry 1 for a single tap on any nonland permanent. The upside lives in the second ability, which reads off the number of cards viewed, so every larger scry source stacked alongside it scales the tap count in lockstep. A scry 2 from elsewhere becomes two taps; a scry 3 becomes a soft Falter that can freeze a wall of blockers, a mana rock, or a creature poised to swing back, blue's answer to Icy Manipulator built out of your own library manipulation. The 3/2 body is content to charge into that plan, feeding its own scry each combat and cracking a lane open by tapping whatever would have stopped the swing. It belongs to a quiet design lineage: cards that take a low-stakes value keyword, usually there just to tidy the top of your deck, and bolt an active board lever onto its resolution so the habit of scrying starts pressing on the game rather than only on your draws.