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."

Tamiyo, Inquisitive Student

Flying
Whenever Tamiyo, Inquisitive Student attacks, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: 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.

Tamiyo, Inquisitive Student // Tamiyo, Seasoned Scholar

Duelist of the Mind

Flying, vigilance
Duelist of the Mind's power is equal to the number of cards you've drawn this turn.
Whenever you commit a crime, you may draw a card. If you do, discard a card. This ability triggers only once each turn.

Ponder

Look at the top three cards of your library, then put them back in any order. You may shuffle.
Draw a card.

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

Emrakul's Messenger

Devoid (This card has no color.)
Flying
Whenever you draw your second card each turn, create a 0/1 colorless Eldrazi Spawn creature token with "Sacrifice this creature: Add {C}."

On the Trail

Whenever you draw your second card each turn, you may put a land card from your hand onto the battlefield tapped.