Basilisk Collar

Equipped creature has deathtouch and lifelink. (Any amount of damage it deals to a creature is enough to destroy it. Damage dealt by this creature also causes you to gain that much life.)
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Izzet Boilerworks

This land enters tapped.
When this land enters, return a land you control to its owner's hand.
{T}: Add {U}{R}.

Kefnet the Mindful

Flying, indestructible
Kefnet can't attack or block unless you have seven or more cards in hand.
{3}{U}: Draw a card, then you may return a land you control to its owner's hand.

Venser's Journal

You have no maximum hand size.
At the beginning of your upkeep, you gain 1 life for each card in your hand.

The Locust God

Flying
Whenever you draw a card, create a 1/1 blue and red Insect creature token with flying and haste.
{2}{U}{R}: Draw a card, then discard a card.
When The Locust God dies, return it to its owner's hand at the beginning of the next end step.

Niv-Mizzet, the Firemind

Flying
Whenever you draw a card, Niv-Mizzet deals 1 damage to any target.
{T}: Draw a card.

Decanter of Endless Water

You have no maximum hand size.
{T}: Add one mana of any color.

Donna Noble

Soulbond (You may pair this creature with another unpaired creature when either enters. They remain paired for as long as you control both of them.)
Whenever Donna Noble or a creature it's paired with is dealt damage, Donna Noble deals that much damage to target opponent.
Doctor's companion (You can have two commanders if the other is the Doctor.)

Shivan Reef

{T}: Add {C}.
{T}: Add {U} or {R}. This land deals 1 damage to you.

Black Vise

As this artifact enters, choose an opponent.
At the beginning of the chosen player's upkeep, this artifact deals X damage to that player, where X is the number of cards in their hand minus 4.

Omen Hawker

{T}: Add {C}{U}. Spend this mana only to activate abilities.

Willbreaker

Whenever a creature an opponent controls becomes the target of a spell or ability you control, gain control of that creature for as long as you control this creature.

Body of Knowledge

Body of Knowledge's power and toughness are each equal to the number of cards in your hand.
You have no maximum hand size.
Whenever this creature is dealt damage, draw that many cards.

Soramaro, First to Dream

Flying
Soramaro's power and toughness are each equal to the number of cards in your hand.
{4}, Return a land you control to its owner's hand: Draw a card.

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

Illusory Ambusher

Flash (You may cast this spell any time you could cast an instant.)
Whenever this creature is dealt damage, draw that many cards.

Island

Feldon, Ronom Excavator

Haste
Feldon can't block.
Whenever Feldon is dealt damage, exile that many cards from the top of your library. Choose one of them. Until the end of your next turn, you may play that card.

Viseling

At the beginning of each opponent's upkeep, this creature deals X damage to that player, where X is the number of cards in their hand minus 4.

Command Tower

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

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Mana Geyser

Add {R} for each tapped land your opponents control.

Spellbook

Irencrag Pyromancer

Whenever you draw your second card each turn, this creature deals 3 damage to any target.

Nin, the Pain Artist

{X}{U}{R}, {T}: Nin deals X damage to target creature. That creature's controller draws X cards.

Stuffy Doll

Indestructible
As this creature enters, choose a player.
Whenever this creature is dealt damage, it deals that much damage to the chosen player.
{T}: This creature deals 1 damage to itself.

Molten Psyche

Each player shuffles the cards from their hand into their library, then draws that many cards.
Metalcraft — If you control three or more artifacts, Molten Psyche deals damage to each opponent equal to the number of cards that player has drawn this turn.

Howlpack Avenger

Whenever a permanent you control is dealt damage, this creature deals that much damage to any target.
{1}{R}: This creature gets +2/+0 until end of turn.
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Ill-Tempered Loner

Whenever this creature is dealt damage, it deals that much damage to any target.
{1}{R}: This creature gets +2/+0 until end of turn.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Ill-Tempered Loner // Howlpack Avenger

Sol Ring

Syr Elenora, the Discerning

Syr Elenora's power is equal to the number of cards in your hand.
When Syr Elenora enters, draw a card.
Spells your opponents cast that target Syr Elenora cost {2} more to cast.

Solemn Simulacrum

When this creature enters, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.
When this creature dies, you may draw a card.

Bulwark

At the beginning of your upkeep, this enchantment deals X damage to target opponent, where X is the number of cards in your hand minus the number of cards in that player's hand.

Locus of Enlightenment

Locus of Enlightenment has each activated ability of the exiled cards used to craft it. You may activate each of those abilities only once each turn.
Whenever you activate an ability that isn't a mana ability, copy it. You may choose new targets for the copy.

The Enigma Jewel

The Enigma Jewel enters tapped.
{T}: Add {C}{C}. Spend this mana only to activate abilities.
Craft with four or more nonlands with activated abilities {8}{U} ({8}{U}, Exile this artifact, Exile the four or more from among other permanents you control and/or cards in your graveyard: Return this card transformed under its owner's control. Craft only as a sorcery.)

The Enigma Jewel // Locus of Enlightenment

Nadir Kraken

Whenever you draw a card, you may pay {1}. If you do, put a +1/+1 counter on this creature and create a 1/1 blue Tentacle creature token.

Thought Vessel

Arcane Signet

Thundering Djinn

Flying
Whenever this creature attacks, it deals damage to any target equal to the number of cards you've drawn this turn.

Wizard Class

(Gain the next level as a sorcery to add its ability.)
You have no maximum hand size.
{2}{U}: Level 2
When this Class becomes level 2, draw two cards.
{4}{U}: Level 3
Whenever you draw a card, put a +1/+1 counter on target creature you control.

Tomoya the Revealer

{3}{U}{U}, {T}: Target player draws X cards, where X is the number of cards in your hand.

Jushi Apprentice

{2}{U}, {T}: Draw a card. If you have nine or more cards in hand, flip this creature.

Jushi Apprentice // Tomoya the Revealer

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.

Hand of Vecna

At the beginning of combat on your turn, equipped creature or a creature you control named Vecna gets +X/+X until end of turn, where X is the number of cards in your hand.
Equip—Pay 1 life for each card in your hand.
Equip {2}

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice this artifact: Draw a card.

Mountain

Niv-Mizzet, Parun

This spell can't be countered.
Flying
Whenever you draw a card, Niv-Mizzet deals 1 damage to any target.
Whenever a player casts an instant or sorcery spell, you draw a card.

Temple of the False God

{T}: Add {C}{C}. Activate only if you control five or more lands.

Triskaidekaphile

You have no maximum hand size.
At the beginning of your upkeep, if you have exactly thirteen cards in your hand, you win the game.
{3}{U}: Draw a card.

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}

Aeon Chronicler

Aeon Chronicler's power and toughness are each equal to the number of cards in your hand.
Suspend X—{X}{3}{U}. X can't be 0.
Whenever a time counter is removed from Aeon Chronicler while it's exiled, draw a card.

Arcbond

Choose target creature. Whenever that creature is dealt damage this turn, it deals that much damage to each other creature and each player.

Cascade Bluffs

{T}: Add {C}.
{U/R}, {T}: Add {U}{U}, {U}{R}, or {R}{R}.

Folio of Fancies

Players have no maximum hand size.
{X}{X}, {T}: Each player draws X cards.
{2}{U}, {T}: Each opponent mills cards equal to the number of cards in their hand.

Izzet Signet

Inner Fire

Adamaro, First to Desire

Adamaro's power and toughness are each equal to the number of cards in the hand of the opponent with the most cards in hand.

Gaze of Adamaro

Gaze of Adamaro deals damage to target player equal to the number of cards in that player's hand.

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.

Talisman of Creativity

{T}: Add {C}.
{T}: Add {U} or {R}. This artifact deals 1 damage to you.

Runeflare Trap

If an opponent drew three or more cards this turn, you may pay {R} rather than pay this spell's mana cost.
Runeflare Trap deals damage to target player equal to the number of cards in that player's hand.

Brash Taunter

Indestructible
Whenever this creature is dealt damage, it deals that much damage to target opponent.
{2}{R}, {T}: This creature fights another target creature.

Sturmgeist

Flying
Sturmgeist's power and toughness are each equal to the number of cards in your hand.
Whenever this creature deals combat damage to a player, draw a card.

Needletooth Raptor

Enrage — Whenever this creature is dealt damage, it deals 5 damage to target creature an opponent controls.

Ominous Seas

Whenever you draw a card, put a foreshadow counter on this enchantment.
Remove eight foreshadow counters from this enchantment: Create an 8/8 blue Kraken creature token.
Cycling {2} ({2}, Discard this card: Draw a card.)

Chasm Skulker

Whenever you draw a card, put a +1/+1 counter on this creature.
When this creature dies, create X 1/1 blue Squid creature tokens with islandwalk, where X is the number of +1/+1 counters on this creature. (They can't be blocked as long as defending player controls an Island.)

Propaganda

Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

Creepy Doll

Indestructible
Whenever this creature deals combat damage to a creature, flip a coin. If you win the flip, destroy that creature.

Counterspell

Fiendlash

Equipped creature gets +2/+0 and has reach.
Whenever equipped creature is dealt damage, it deals damage equal to its power to target player or planeswalker.
Equip {2}{R}

Faithless Looting

Draw two cards, then discard two cards.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

The Watcher in the Water

The Watcher in the Water enters tapped with nine stun counters on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)
Whenever you draw a card during an opponent's turn, create a 1/1 blue Tentacle creature token.
Whenever a Tentacle you control dies, untap up to one target Kraken and put a stun counter on up to one target nonland permanent.

Lonely Sandbar

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

Wrathful Red Dragon

Flying
Whenever a Dragon you control is dealt damage, it deals that much damage to any target that isn't a Dragon.

Psychosis Crawler

Psychosis Crawler's power and toughness are each equal to the number of cards in your hand.
Whenever you draw a card, each opponent loses 1 life.

Darksteel Plate

Indestructible
Equipped creature has indestructible.
Equip {2}

Blasphemous Act

This spell costs {1} less to cast for each creature on the battlefield.
Blasphemous Act deals 13 damage to each creature.