Nimble Obstructionist

Flash
Flying
Cycling {2}{U} ({2}{U}, Discard this card: Draw a card.)
When you cycle this card, counter target activated or triggered ability you don't control.

Ominous Sphinx

Flying
Whenever you cycle or discard a card, target creature an opponent controls gets -2/-0 until end of turn.

Proven Combatant

Eternalize {4}{U}{U} ({4}{U}{U}, Exile this card from your graveyard: Create a token that's a copy of it, except it's a 4/4 black Zombie Human Warrior with no mana cost. Eternalize only as a sorcery.)

Riddleform

Whenever you cast a noncreature spell, you may have this enchantment become a 3/3 Sphinx creature with flying in addition to its other types until end of turn.
{2}{U}: Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Seer of the Last Tomorrow

{U}, {T}, Discard a card: Target player mills three cards.

Sinuous Striker

{U}: This creature gets +1/-1 until end of turn.
Eternalize—{3}{U}{U}, Discard a card. ({3}{U}{U}, Discard a card, Exile this card from your graveyard: Create a token that's a copy of it, except it's a 4/4 black Zombie Snake Warrior with no mana cost. Eternalize only as a sorcery.)

Spellweaver Eternal

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Afflict 2 (Whenever this creature becomes blocked, defending player loses 2 life.)

Strategic Planning

Look at the top three cards of your library. Put one of them into your hand and the rest into your graveyard.

Striped Riverwinder

Hexproof (This creature can't be the target of spells or abilities your opponents control.)
Cycling {U} ({U}, Discard this card: Draw a card.)

Supreme Will

Choose one —
• Counter target spell unless its controller pays {3}.
• Look at the top four cards of your library. Put one of them into your hand and the rest on the bottom of your library in any order.

Aven of Enduring Hope

Flying
When this creature enters, you gain 3 life.

Swarm Intelligence

Whenever you cast an instant or sorcery spell, you may copy that spell. You may choose new targets for the copy.

Tragic Lesson

Draw two cards. Then discard a card unless you return a land you control to its owner's hand.

Unesh, Criosphinx Sovereign

Flying
Sphinx spells you cast cost {2} less to cast.
Whenever Unesh or another Sphinx you control enters, reveal the top four cards of your library. An opponent separates those cards into two piles. Put one pile into your hand and the other into your graveyard.

Unquenchable Thirst

Enchant creature
When this Aura enters, if you control a Desert or there is a Desert card in your graveyard, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.

Unsummon

Return target creature to its owner's hand.

Hour of Devastation