Knight of the Skyward Eye

Knight of the Skyward Eye sees essentially no competitive play in Legacy, Modern, or Vintage — the formats where two-mana creatures need to do something immediately, and a conditional pump ability that costs four more mana doesn't qualify. In Pauper it's legal but irrelevant, squeezed out by commons that generate card advantage or apply pressure far more efficiently. Commander is the only context where the mana investment is plausibly affordable, but even there Knight of the Skyward Eye competes against two-drops that draw cards, ramp, or create tokens — and loses that comparison badly unless the deck has a specific reason to exile its own library.