Sinister Cryologist

When this creature enters, target creature an opponent controls gets -3/-0 until end of turn.
Warp {U} (You may cast this card from your hand for its warp cost. Exile this creature at the beginning of the next end step, then you may cast it from exile on a later turn.)

Livaan, Cultist of Tiamat

Whenever you cast a noncreature spell, target creature gets +X/+0 until end of turn, where X is that spell's mana value.
Choose a Background (You can have a Background as a second commander.)

Counterspell

Dwindle

Enchant creature
Enchanted creature gets -6/-0.
When enchanted creature blocks, destroy it. (The attacking creature remains blocked.)

Mana Leak

Counter target spell unless its controller pays {3}.

Highland Lake

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

Miscast

Counter target instant or sorcery spell unless its controller pays {3}.

Innocent Bystander

Whenever this creature is dealt 3 or more damage, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

An Unearthly Child

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I, II, III — Reveal cards from the top of your library until you reveal a Doctor card, a card with doctor's companion, or a Vehicle card. Put that card into your hand and the rest on the bottom of your library in a random order.

Corridor Monitor

When this creature enters, untap target artifact or creature you control.

Curious Inquiry

Enchant creature
Enchanted creature gets +1/+1 and has "Whenever this creature deals combat damage to a player, investigate." (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Stormcarved Coast

This land enters tapped unless you control two or more other lands.
{T}: Add {U} or {R}.

Island

Run Away Together

Choose two target creatures controlled by different players. Return those creatures to their owners' hands.

Nemesis Phoenix

Flying
{2}{R}: Return this card from your graveyard to the battlefield tapped and attacking. Activate only during the declare attackers step and only if you're attacking two or more opponents.

Campfire

{1}, {T}: You gain 2 life.
{2}, {T}, Exile this artifact: Put all commanders you own from the command zone and from your graveyard into your hand. Then shuffle your graveyard into your library.

Mental Modulation

This spell costs {1} less to cast during your turn.
Tap target artifact or creature.
Draw a card.

Doc Ock, Sinister Scientist

As long as there are eight or more cards in your graveyard, Doc Ock has base power and toughness 8/8.
As long as you control another Villain, Doc Ock has hexproof. (He can't be the target of spells or abilities your opponents control.)

Electrodominance

Electrodominance deals X damage to any target. You may cast a spell with mana value X or less from your hand without paying its mana cost.

Unravel

Counter target spell. If the amount of mana spent to cast that spell was less than its mana value, you draw a card.

Ripscale Predator

Menace (This creature can't be blocked except by two or more creatures.)

Abrade

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

Izzet Signet

Stern Scolding

Counter target creature spell with power or toughness 2 or less.

Visions of Duplicity

Exchange control of two target creatures you don't control.
Flashback {8}{U}{U}. This spell costs {X} less to cast this way, where X is the greatest mana value of a commander you own on the battlefield or in the command zone. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Subterranean Schooner

Whenever this Vehicle attacks, target creature that crewed it this turn explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on that creature, then put the card back or put it into your graveyard.)
Crew 1

Envelop

Thrill of Possibility

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

Alania, Divergent Storm

Whenever you cast a spell, if it's the first instant spell, the first sorcery spell, or the first Otter spell other than Alania you've cast this turn, you may have target opponent draw a card. If you do, copy that spell. You may choose new targets for the copy.

Switcheroo

Exchange control of two target creatures.

True-Name Nemesis

As this creature enters, choose a player.
This creature has protection from the chosen player.

Desculpting Blast

Return target nonland permanent to its owner's hand. If it was attacking, create a 1/1 colorless Drone artifact creature token with flying and "This token can block only creatures with flying."

Arcane Signet

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

Sphinx of Uthuun

Flying
When this creature enters, reveal the top five cards of your library. An opponent separates those cards into two piles. Put one pile into your hand and the other into your graveyard.

Apex of Power

Exile the top seven cards of your library. Until end of turn, you may cast spells from among them.
If this spell was cast from your hand, add ten mana of any one color.

Leyline of Combustion

If this card is in your opening hand, you may begin the game with it on the battlefield.
Whenever you and/or at least one permanent you control becomes the target of a spell or ability an opponent controls, this enchantment deals 2 damage to that player.

Nyssa of Traken

You have no maximum hand size.
Sonic Booster — Whenever Nyssa of Traken attacks, sacrifice any number of artifacts. When you sacrifice one or more artifacts this way, tap up to that many target creatures and draw that many cards.
Doctor's companion (You can have two commanders if the other is the Doctor.)

Fire Diamond

This artifact enters tapped.
{T}: Add {R}.

The Chase Is On

Target creature gets +3/+0 and gains first strike until end of turn. Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Deduce

Draw a card. Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Pieces of the Puzzle

Reveal the top five cards of your library. Put up to two instant and/or sorcery cards from among them into your hand and the rest into your graveyard.

Minotaur Aggressor

Swiftwater Cliffs

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {U} or {R}.

Hotfoot Gnome

Haste
{T}: Another target creature gains haste until end of turn.

Thought Scour

Target player mills two cards.
Draw a card.

Otherworldly Gaze

Surveil 3. (Look at the top three cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)
Flashback {1}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Cackling Counterpart

Create a token that's a copy of target creature you control.
Flashback {5}{U}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Doublecast

When you next cast an instant or sorcery spell this turn, copy that spell. You may choose new targets for the copy.

Sword Coast Sailor

Commander creatures you own have "Whenever this creature attacks a player, if no opponent has more life than that player, this creature can't be blocked this turn."

Candlekeep Sage

Commander creatures you own have "When this creature enters or leaves the battlefield, draw a card."

Jace Beleren

+2: Each player draws a card.
−1: Target player draws a card.
−10: Target player mills twenty cards.

Mystic Archaeologist

Burning-Tree Vandal

Riot (This creature enters with your choice of a +1/+1 counter or haste.)
Whenever this creature attacks, you may discard a card. If you do, draw a card.

Amazing Acrobatics

Choose one or both —
• Counter target spell.
• Tap one or two target creatures.

Enter the Enigma

Target creature can't be blocked this turn.
Draw a card.

Swashbuckler Extraordinaire

When this creature enters, create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")
Whenever you attack, you may sacrifice one or more Treasures. When you do, up to that many target creatures gain double strike until end of turn.

Mountain

Vibrant Cityscape

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

Sol Ring

Fateful Showdown

Fateful Showdown deals damage to any target equal to the number of cards in your hand. Discard all the cards in your hand, then draw that many cards.

Capture Sphere

Flash (You may cast this spell any time you could cast an instant.)
Enchant creature
When this Aura enters, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.

Charmed Sleep

Enchant creature
When this Aura enters, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.

Hidden Volcano

This land enters tapped.
{T}: Add {R}.
{4}{R}, {T}, Sacrifice this land: Discover 4. Activate only as a sorcery. (Exile cards from the top of your library until you exile a nonland card with mana value 4 or less. Cast it without paying its mana cost or put it into your hand. Put the rest on the bottom in a random order.)

Scroll Thief

Whenever this creature deals combat damage to a player, draw a card.

Sleep

Tap all creatures target player controls. Those creatures don't untap during that player's next untap step.

Think Twice

Draw a card.
Flashback {2}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Scholar of Stars

When this creature enters, if you control an artifact, draw a card.

Trenzalore Clocktower

{T}: Add {U}. Put a time counter on Trenzalore Clocktower.
{1}{U}, {T}, Remove twelve time counters from Trenzalore Clocktower and exile it: Shuffle your graveyard and hand into your library, then draw seven cards. Activate only if you control a Time Lord.

Divination

Adric, Mathematical Genius

{2}{U}, {T}: Copy target activated or triggered ability you control. You may choose new targets for the copy.
Ultimate Sacrifice — {1}{U}, Sacrifice Adric: Counter target activated or triggered ability.
Doctor's companion (You can have two commanders if the other is the Doctor.)

Pearl of Wisdom

This spell costs {1} less to cast if you control an Otter.
Draw two cards.

Red Sun's Twilight

Destroy up to X target artifacts. If X is 5 or more, for each artifact destroyed this way, create a token that's a copy of it. Those tokens gain haste. Exile them at the beginning of the next end step.

Pinnacle Emissary

Whenever you cast an artifact spell, create a 1/1 colorless Drone artifact creature token with flying and "This token can block only creatures with flying."
Warp {U/R} (You may cast this card from your hand for its warp cost. Exile this creature at the beginning of the next end step, then you may cast it from exile on a later turn.)