Aquamoeba

Discard a card: Switch Aquamoeba's power and toughness until end of turn.

Wormfang Drake

Flying
When Wormfang Drake enters, sacrifice it unless you exile a creature you control other than Wormfang Drake.
When Wormfang Drake leaves the battlefield, return the exiled card to the battlefield under its owner's control.

Juggernaut

Juggernaut attacks each combat if able.
Juggernaut can't be blocked by Walls.

Wretched Anurid

Whenever another creature enters, you lose 1 life.

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice Mind Stone: Draw a card.

Frantic Search

Draw two cards, then discard two cards. Untap up to three lands.

Yawgmoth, Thran Physician

Protection from Humans
Pay 1 life, Sacrifice another creature: Put a -1/-1 counter on up to one target creature and draw a card.
{B}{B}, Discard a card: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Dragon Blood

{3}, {T}: Put a +1/+1 counter on target creature.

Dark Withering

Destroy target nonblack creature.
Madness {B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Death

Return target creature card from your graveyard to the battlefield. You lose life equal to its mana value.

Life

All lands you control become 1/1 creatures until end of turn. They're still lands.

Life // Death

Ovinomancer

When Ovinomancer enters, sacrifice it unless you return three basic lands you control to their owner's hand.
{T}, Return Ovinomancer to its owner's hand: Destroy target creature. It can't be regenerated. That creature's controller creates a 0/1 green Sheep creature token.

Island

Ovinize

Until end of turn, target creature loses all abilities and has base power and toughness 0/1.

Ornithopter

Necrosavant

{3}{B}{B}, Sacrifice a creature: Return Necrosavant from your graveyard to the battlefield. Activate only during your upkeep.

Recoil

Return target permanent to its owner's hand. Then that player discards a card.

Millikin

{T}, Mill a card: Add {C}. (To mill a card, put the top card of your library into your graveyard.)

Duress

Target opponent reveals their hand. You choose a noncreature, nonland card from it. That player discards that card.

Hermetic Study

Enchant creature
Enchanted creature has "{T}: This creature deals 1 damage to any target."

Dodecapod

If a spell or ability an opponent controls causes you to discard Dodecapod, put it onto the battlefield with two +1/+1 counters on it instead of putting it into your graveyard.

Swamp

Phyrexian Scuta

Kicker—Pay 3 life. (You may pay 3 life in addition to any other costs as you cast this spell.)
If Phyrexian Scuta was kicked, it enters with two +1/+1 counters on it.

Hyalopterous Lemure

{0}: Hyalopterous Lemure gets -1/-0 and gains flying until end of turn.

Street Wraith

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)
Cycling—Pay 2 life. (Pay 2 life, Discard this card: Draw a card.)

Flesh Reaver

Whenever Flesh Reaver deals damage to a creature or opponent, Flesh Reaver deals that much damage to you.

Thieving Magpie

Flying (This creature can't be blocked except by creatures with flying or reach.)
Whenever Thieving Magpie deals damage to an opponent, draw a card.

Circular Logic

Counter target spell unless its controller pays {1} for each card in your graveyard.
Madness {U} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Jalum Tome

{2}, {T}: Draw a card, then discard a card.

Urborg Syphon-Mage

{2}{B}, {T}, Discard a card: Each other player loses 2 life. You gain life equal to the life lost this way.

Mishra's Factory

{T}: Add {C}.
{1}: Mishra's Factory becomes a 2/2 Assembly-Worker artifact creature until end of turn. It's still a land.
{T}: Target Assembly-Worker creature gets +1/+1 until end of turn.

Impulse

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.