Terror

Destroy target nonartifact, nonblack creature. It can't be regenerated.

Agatha of the Vile Cauldron

Activated abilities of creatures you control cost {X} less to activate, where X is Agatha's power. This effect can't reduce the mana in that cost to less than one mana.
{4}{R}{G}: Other creatures you control get +1/+1 and gain trample and haste until end of turn.

Black Lotus

{T}, Sacrifice this artifact: Add three mana of any one color.

Sneak Attack

{R}: You may put a creature card from your hand onto the battlefield. That creature gains haste. Sacrifice the creature at the beginning of the next end step.

Halo Fountain

{W}, {T}, Untap a tapped creature you control: Create a 1/1 green and white Citizen creature token.
{W}{W}, {T}, Untap two tapped creatures you control: Draw a card.
{W}{W}{W}{W}{W}, {T}, Untap fifteen tapped creatures you control: You win the game.

Training Grounds

Activated abilities of creatures you control cost {2} less to activate. This effect can't reduce the mana in that cost to less than one mana.

Royal Assassin

Avacyn, Guardian Angel

Flying, vigilance
{1}{W}: Prevent all damage that would be dealt to another target creature this turn by sources of the color of your choice.
{5}{W}{W}: Prevent all damage that would be dealt to target player or planeswalker this turn by sources of the color of your choice.

Have

Agatha's Soul Cauldron

You may spend mana as though it were mana of any color to activate abilities of creatures you control.
Creatures you control with +1/+1 counters on them have all activated abilities of all creature cards exiled with Agatha's Soul Cauldron.
{T}: Exile target card from a graveyard. When a creature card is exiled this way, put a +1/+1 counter on target creature you control.

Proxy

Chromatic Lantern

Lands you control have "{T}: Add one mana of any color."
{T}: Add one mana of any color.

Evolving Wilds

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Atarka Pummeler

Formidable — {3}{R}{R}: Creatures you control gain menace until end of turn. Activate only if creatures you control have total power 8 or greater. (They can't be blocked except by two or more creatures.)

Clever Conjurer

Mage Hand — {T}: Untap target permanent not named Clever Conjurer. Activate only as a sorcery.

Tribute Mage

When this creature enters, you may search your library for an artifact card with mana value 2, reveal that card, put it into your hand, then shuffle.

Disenchant

Captivating Crew

{3}{R}: Gain control of target creature an opponent controls until end of turn. Untap that creature. It gains haste until end of turn. Activate only as a sorcery.

Worldly Tutor

Search your library for a creature card, reveal it, then shuffle and put the card on top.

Mist Dragon

{0}: This creature gains flying. (This effect lasts indefinitely.)
{0}: This creature loses flying. (This effect lasts indefinitely.)
{3}{U}{U}: This creature phases out. (While it's phased out, it's treated as though it doesn't exist. It phases in before you untap during your next untap step.)

Birds of Paradise

Tamiyo's Safekeeping

Target permanent you control gains hexproof and indestructible until end of turn. You gain 2 life. (A permanent with hexproof and indestructible can't be the target of spells or abilities your opponents control. Damage and effects that say "destroy" don't destroy it.)

Shivan Dragon

Flying
{R}: This creature gets +1/+0 until end of turn.

Horseshoe Crab

Island

Gigantomancer

{1}: Target creature you control has base power and toughness 7/7 until end of turn.

Hinterland Harbor

This land enters tapped unless you control a Forest or an Island.
{T}: Add {G} or {U}.

Garth One-Eye

{T}: Choose a card name that hasn't been chosen from among Disenchant, Braingeyser, Terror, Shivan Dragon, Regrowth, and Black Lotus. Create a copy of the card with the chosen name. You may cast the copy. (You still pay its costs.)

Fauna Shaman

{G}, {T}, Discard a creature card: Search your library for a creature card, reveal it, put it into your hand, then shuffle.

Experiment Kraj

Experiment Kraj has all activated abilities of each other creature with a +1/+1 counter on it.
{T}: Put a +1/+1 counter on target creature.

Arcanis the Omnipotent

{T}: Draw three cards.
{2}{U}{U}: Return Arcanis to its owner's hand.

Mother of Runes

{T}: Target creature you control gains protection from the color of your choice until end of turn.

Fabricate

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

Mountain

Akim, the Soaring Wind

Flying
Whenever you create one or more tokens for the first time each turn, create a 1/1 white Bird creature token with flying.
{3}{U}{R}{W}: Creature tokens you control gain double strike until end of turn.

Godsire

Vigilance
{T}: Create an 8/8 Beast creature token that's red, green, and white.

Aron, Benalia's Ruin

Menace (This creature can't be blocked except by two or more creatures.)
{W}{B}, {T}, Sacrifice another creature: Put a +1/+1 counter on each creature you control.

Kamahl, Pit Fighter

Haste (This creature can attack and {T} as soon as it comes under your control.)
{T}: Kamahl deals 3 damage to any target.

Thassa, God of the Sea

Indestructible
As long as your devotion to blue is less than five, Thassa isn't a creature. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)
At the beginning of your upkeep, scry 1.
{1}{U}: Target creature you control can't be blocked this turn.

Regrowth

Return target card from your graveyard to your hand.

Braingeyser

Heroes' Bane

This creature enters with four +1/+1 counters on it.
{2}{G}{G}: Put X +1/+1 counters on this creature, where X is its power.

Rootbound Crag

This land enters tapped unless you control a Mountain or a Forest.
{T}: Add {R} or {G}.

Forest

Battlemage's Bracers

Equipped creature has haste.
Whenever an ability of equipped creature is activated, if it isn't a mana ability, you may pay {1}. If you do, copy that ability. You may choose new targets for the copy.
Equip {2}

Conclave Guildmage

{G}, {T}: Creatures you control gain trample until end of turn.
{5}{W}, {T}: Create a 2/2 green and white Elf Knight creature token with vigilance.

Zabaz, the Glimmerwasp

Modular 1
If a modular triggered ability would put one or more +1/+1 counters on a creature you control, that many plus one +1/+1 counters are put on it instead.
{R}: Destroy target artifact you control.
{W}: Zabaz gains flying until end of turn.