Prevent all combat damage that would be dealt this turn.

About Face

Switch target creature's power and toughness until end of turn.

Antagonize

Target creature gets +4/+3 until end of turn.

Leela, Sevateem Warrior

Whenever an opponent draws a card except the first one they draw in each of their draw steps, put a +1/+1 counter on Leela.
Doctor's companion (You can have two commanders if the other is the Doctor.)

Abrade

Choose one —
• Abrade deals 3 damage to target creature.
• Destroy target artifact.

Dutiful Replicator

When this creature enters, you may pay {1}. When you do, create a token that's a copy of target token you control not named Dutiful Replicator.

Voltaic Key

Battlegrowth

Ketria Triome

({T}: Add {G}, {U}, or {R}.)
This land enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Chaos Charm

Choose one —
• Destroy target Wall.
• Chaos Charm deals 1 damage to target creature.
• Target creature gains haste until end of turn.

Ripples of Potential

Proliferate, then choose any number of permanents you control that had a counter put on them this way. Those permanents phase out. (To proliferate, choose any number of permanents and/or players, then give each another counter of each kind already there. Treat phased-out permanents and anything attached to them as though they don't exist until their controller's next turn.)

Words of Wisdom

You draw two cards, then each other player draws a card.

Double Major

Copy target creature spell you control, except it isn't legendary if the spell is legendary. (A copy of a creature spell becomes a token.)

Demand Answers

As an additional cost to cast this spell, sacrifice an artifact or discard a card.
Draw two cards.

Treasure Chest

{4}, Sacrifice this artifact: Roll a d20.
1 | Trapped! — You lose 3 life.
2—9 | Create five Treasure tokens.
10—19 | You gain 3 life and draw three cards.
20 | Search your library for a card. If it's an artifact card, you may put it onto the battlefield. Otherwise, put that card into your hand. Then shuffle.

Karn, the Great Creator

Activated abilities of artifacts your opponents control can't be activated.
+1: Until your next turn, up to one target noncreature artifact becomes an artifact creature with power and toughness each equal to its mana value.
−2: You may reveal an artifact card you own from outside the game or choose a face-up artifact card you own in exile. Put that card into your hand.

Voracious Reader

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Instant and sorcery spells you cast cost {1} less to cast.

Curious Homunculus

{T}: Add {C}. Spend this mana only to cast an instant or sorcery spell.
At the beginning of your upkeep, if there are three or more instant and/or sorcery cards in your graveyard, transform this creature.

Curious Homunculus // Voracious Reader

Frontier Bivouac

This land enters tapped.
{T}: Add {G}, {U}, or {R}.

Snap

Return target creature to its owner's hand. Untap up to two lands.

Accelerate

Target creature gains haste until end of turn.
Draw a card.

Tower Winder

Reach, deathtouch
When this creature enters, search your library and/or graveyard for a card named Command Tower, reveal it, and put it into your hand. If you search your library this way, shuffle.

Active Volcano

Choose one —
• Destroy target blue permanent.
• Return target Island to its owner's hand.

Urza's Saga

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — This Saga gains "{T}: Add {C}."
II — This Saga gains "{2}, {T}: Create a 0/0 colorless Construct artifact creature token with 'This token gets +1/+1 for each artifact you control.'"
III — Search your library for an artifact card with mana cost {0} or {1}, put it onto the battlefield, then shuffle.

Splendid Reclamation

Return all land cards from your graveyard to the battlefield tapped.

Sculpting Steel

You may have this artifact enter as a copy of any artifact on the battlefield.

Unblinking Observer

{T}: Add {U}. Spend this mana only to pay a disturb cost or cast an instant or sorcery spell.

Battle Hymn

Riku of Two Reflections

Whenever you cast an instant or sorcery spell, you may pay {U}{R}. If you do, copy that spell. You may choose new targets for the copy.
Whenever another nontoken creature you control enters, you may pay {G}{U}. If you do, create a token that's a copy of that creature.

Urza's Mine

{T}: Add {C}. If you control an Urza's Power-Plant and an Urza's Tower, add {C}{C} instead.

Rousing Refrain

Add {R} for each card in target opponent's hand. Until end of turn, you don't lose this mana as steps and phases end. Exile Rousing Refrain with three time counters on it.
Suspend 3—{1}{R} (Rather than cast this card from your hand, you may pay {1}{R} and exile it with three time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)

Ancestors' Aid

Target creature gets +2/+0 and gains first strike until end of turn.
Create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Altar of Dementia

Sacrifice a creature: Target player mills cards equal to the sacrificed creature's power.

Barge In

Target attacking creature gets +2/+2 until end of turn. Each attacking non-Human creature gains trample until end of turn.

Vision Skeins

Command Tower

{T}: Add one mana of any color in your commander's color identity.

Boomerang

Return target permanent to its owner's hand.

Manamorphose

Add two mana in any combination of colors.
Draw a card.

Scrawling Crawler

At the beginning of your upkeep, each player draws a card.
Whenever an opponent draws a card, that player loses 1 life.

Benefactor's Draught

Untap all creatures. Until end of turn, whenever a creature an opponent controls blocks, draw a card.
Draw a card.

Urza's Tower

{T}: Add {C}. If you control an Urza's Mine and an Urza's Power-Plant, add {C}{C}{C} instead.

Urza's Power Plant

{T}: Add {C}. If you control an Urza's Mine and an Urza's Tower, add {C}{C} instead.

Narset's Reversal

Copy target instant or sorcery spell, then return it to its owner's hand. You may choose new targets for the copy.

Manifold Key

{1}, {T}: Untap another target artifact.
{3}, {T}: Target creature can't be blocked this turn.

Isochron Scepter

Imprint — When this artifact enters, you may exile an instant card with mana value 2 or less from your hand.
{2}, {T}: You may copy the exiled card. If you do, you may cast the copy without paying its mana cost.

Fighting Chance

For each blocking creature, flip a coin. If you win the flip, prevent all combat damage that would be dealt by that creature this turn.