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 attacks, investigate. (Create a Clue token. It's an artifact with "{2}, 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.

Tamiyo, Inquisitive Student // Tamiyo, Seasoned Scholar

Daze

You may return an Island you control to its owner's hand rather than pay this spell's mana cost.
Counter target spell unless its controller pays {1}.

Ponder

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

Scalding Tarn

{T}, Pay 1 life, Sacrifice this land: Search your library for an Island or Mountain card, put it onto the battlefield, then shuffle.

Boomerang

Return target permanent to its owner's hand.

Misty Rainforest

{T}, Pay 1 life, Sacrifice this land: Search your library for a Forest or Island card, put it onto the battlefield, then shuffle.

Remand

Counter target spell. If that spell is countered this way, put it into its owner's hand instead of into that player's graveyard.
Draw a card.

Hurkyl's Recall

Return all artifacts target player owns to their hand.

Back to Basics

Nonbasic lands don't untap during their controllers' untap steps.

Quantum Riddler

Flying
When this creature enters, draw a card.
As long as you have one or fewer cards in hand, if you would draw one or more cards, you draw that many cards plus one instead.
Warp {1}{U}

Counterspell

Brainstorm

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

Vapor Snag

Return target creature to its owner's hand. Its controller loses 1 life.

Disrupting Shoal

You may exile a blue card with mana value X from your hand rather than pay this spell's mana cost.
Counter target spell if its mana value is X.

Awoken Horror

When this creature transforms into Awoken Horror, return all non-Horror creatures to their owners' hands.

Thing in the Ice

Defender
This creature enters with four ice counters on it.
Whenever you cast an instant or sorcery spell, remove an ice counter from this creature. Then if it has no ice counters on it, transform it.

Thing in the Ice // Awoken Horror

Murktide Regent

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)
Flying
This creature enters with a +1/+1 counter on it for each instant and sorcery card exiled with it.
Whenever an instant or sorcery card leaves your graveyard, put a +1/+1 counter on this creature.

Mishra's Bauble

{T}, Sacrifice this artifact: Look at the top card of target player's library. Draw a card at the beginning of the next turn's upkeep.

Force of Will

You may pay 1 life and exile a blue card from your hand rather than pay this spell's mana cost.
Counter target spell.

Sea's Claim

Enchant land (Target a land as you cast this. This card enters attached to that land.)
Enchanted land is an Island.

Polluted Delta

{T}, Pay 1 life, Sacrifice this land: Search your library for an Island or Swamp card, put it onto the battlefield, then shuffle.