Goblin Banneret

Mentor on a one-drop is a quiet trick of incentive design. The keyword normally lives on aggressive midsized bodies that want to swing into open boards and grow a wider team, but here the carrier is the smallest thing it can sit on: a 1/1, whose trigger only finds a target with power zero. On its own it mentors almost nothing, since the standard tokens and one-drops it would swing beside sit at 1 power, above its reach. The pump ability is what resolves that tension. Spending mana to push the Banneret to 3/1 raises the ceiling on which attackers it can mentor, so the same investment that makes it hit harder also opens the pool of creatures eligible for a counter: a 3/1 can suddenly hand +1/+1 to the 1-power and 2-power bodies it could never touch unassisted. That coupling is the whole mechanism: power on the source dictates eligibility on the target, and the activated ability is the dial you turn to keep the trigger live as the board fills in around it. It is a deliberately self-limiting engine, a goblin built to make the goblins behind it bigger rather than to carry the beatdown itself, and one that only earns its keyword the turn you pay to make it big enough to lead.