Goblin Researcher

Impulse-draw with a leash. The card exiled on entry does not sit there waiting to be spent whenever: you only get to play it during a turn you attacked with this Goblin, which welds the card advantage to an aggressive posture and denies it to a defender content to hang back and dig. That is a sharper constraint than most red card-draw creatures carry. The usual model hands you the card unconditionally, whether it is Elvish Visionary in green or the countless red cantrips-on-a-stick; this one makes you commit the body to combat first, then rewards the turn you did. A body that dies before it swings leaves the exiled card stranded, so the ability functions as a payoff for keeping the attacker alive and pressuring, not something you drip out at leisure. The two clauses are also worth reading carefully: the exile happens on the enters trigger, the permission to play the card is a separate linked ability, and both are tied to this object. Blink it or reanimate it and you get a fresh object with a fresh exile, but the card the original trigger stashed away is now orphaned; no attack with the new copy will unlock it. The interest is entirely in tying the payoff to the attack step, turning a would-be card-advantage creature into a standing reason to keep pushing damage.