Turtleshell Changeling

Changeling (This card is every creature type.)
{1}{U}: Switch Turtleshell Changeling's power and toughness until end of turn.

Obelisk of Grixis

Deafening Silence

Each player can't cast more than one noncreature spell each turn.

Ghostly Changeling

Changeling (This card is every creature type.)
{1}{B}: Ghostly Changeling gets +1/+1 until end of turn.

Graveborn Muse

At the beginning of your upkeep, you draw X cards and you lose X life, where X is the number of Zombies you control.

Fire-Belly Changeling

Changeling (This card is every creature type.)
{R}: Fire-Belly Changeling gets +1/+0 until end of turn. Activate no more than twice each turn.

Reflecting Pool

{T}: Add one mana of any type that a land you control could produce.

Phage the Untouchable

When Phage the Untouchable enters, if you didn't cast it from your hand, you lose the game.
Whenever Phage deals combat damage to a creature, destroy that creature. It can't be regenerated.
Whenever Phage deals combat damage to a player, that player loses the game.

Sultai Banner

{T}: Add {B}, {G}, or {U}.
{B}{G}{U}, {T}, Sacrifice Sultai Banner: Draw a card.

Putrid Goblin

Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)

Holy Day

Prevent all combat damage that would be dealt this turn.

Greater Auramancy

Other enchantments you control have shroud. (A permanent with shroud can't be the target of spells or abilities.)
Enchanted creatures you control have shroud.

Mardu Banner

{T}: Add {R}, {W}, or {B}.
{R}{W}{B}, {T}, Sacrifice Mardu Banner: Draw a card.

Ephemerate

Exile target creature you control, then return it to the battlefield under its owner's control.
Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)

Noxious Ghoul

Whenever Noxious Ghoul or another Zombie enters, all non-Zombie creatures get -1/-1 until end of turn.

Abzan Banner

{T}: Add {W}, {B}, or {G}.
{W}{B}{G}, {T}, Sacrifice Abzan Banner: Draw a card.

Carrion Feeder

Carrion Feeder can't block.
Sacrifice a creature: Put a +1/+1 counter on Carrion Feeder.

Telepathy

Your opponents play with their hands revealed.

Pestilence

At the beginning of the end step, if no creatures are on the battlefield, sacrifice Pestilence.
{B}: Pestilence deals 1 damage to each creature and each player.

Long-Term Plans

Search your library for a card, then shuffle and put that card third from the top.

Engineered Plague

As Engineered Plague enters, choose a creature type.
All creatures of the chosen type get -1/-1.

Idyllic Tutor

Search your library for an enchantment card, reveal it, put it into your hand, then shuffle.

Viscera Seer

Sacrifice a creature: Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Traumatize

Target player mills half their library, rounded down.

Fool's Demise

Enchant creature
When enchanted creature dies, return that card to the battlefield under your control.
When Fool's Demise is put into a graveyard from the battlefield, return Fool's Demise to its owner's hand.

Screams from Within

Enchant creature
Enchanted creature gets -1/-1.
When enchanted creature dies, return Screams from Within from your graveyard to the battlefield.