Echo, Perceptive Prodigy

The engine here is not the copy: it's the fact that the copy costs almost nothing and can be pointed anywhere. Ability-copying has usually lived on cards that pay a real toll (Strionic Resonator taps and asks for two mana per fire, and only touches triggers) or that fizz once and vanish. This asks for a single mana and a tap, and it reaches both activated and triggered abilities so long as the source is a creature you control. The design tension is entirely in that source restriction: no copying planeswalker loyalty, no copying artifact or enchantment activations, no touching mana abilities at all. What's left is the whole surface of creature value, and the new-targets clause is where the doubling turns into direction. A single-target creature effect (a ping, a bounce, a tutor trigger, a Blink) becomes two effects aimed wherever you like, which is a different thing from merely stacking the same target twice. The 1/4 body with vigilance tells you the card was never meant to attack for a win; the four toughness is there to survive a turn cycle so the tap ability can fire again and again. It is a repeatable engine dressed as a Hero, and its ceiling scales with how many creature abilities you can generate in a turn rather than with anything printed on the card itself.