Tamiyo, Seasoned Scholar

+2: Until your next turn, whenever a creature attacks you or a planeswalker you control, it gets -1/-0 until end of turn.

−3: Return target instant or sorcery card from your graveyard to your hand. If it's a green card, add one mana of any color.

−7: Draw cards equal to half the number of cards in your library, rounded up. You get an emblem with "You have no maximum hand size."

Flying

Whenever Tamiyo attacks, investigate. (Create a Clue token. It's an artifact with ", Sacrifice this token: Draw a card.")

When you draw your third card in a turn, exile Tamiyo, then return her to the battlefield transformed under her owner's control.