Protective Bubble

Enchant creature
Enchanted creature can't be blocked and has shroud. (It can't be the target of spells or abilities.)

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}

Commence the Endgame

This spell can't be countered.
Draw two cards, then amass Zombies X, where X is the number of cards in your hand. (Put X +1/+1 counters on an Army you control. It's also a Zombie. If you don't control an Army, create a 0/0 black Zombie Army creature token first.)

Invisibility

Enchant creature
Enchanted creature can't be blocked except by Walls.

Omniscience

You may cast spells from your hand without paying their mana costs.

Soramaro, First to Dream

Flying
Soramaro, First to Dream'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.

Kianne, Corrupted Memory

As long as Kianne's power is even, you may cast noncreature spells as though they had flash.
As long as Kianne's power is odd, you may cast creature spells as though they had flash.
Whenever you draw a card, put a +1/+1 counter on Kianne.

Nightmarish End

Target creature gets -X/-X until end of turn, where X is the number of cards in your hand.

Manifold Key

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

Prowler's Helm

Equipped creature can't be blocked except by Walls.
Equip {2}

Tezzeret's Gatebreaker

When Tezzeret's Gatebreaker enters, look at the top five cards of your library. You may reveal a blue or artifact card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.
{5}{U}, {T}, Sacrifice Tezzeret's Gatebreaker: Creatures you control can't be blocked this turn.

Whispersilk Cloak

Equipped creature can't be blocked and has shroud. (It can't be the target of spells or abilities.)
Equip {2}

Oneirophage

Flying
Whenever you draw a card, put a +1/+1 counter on Oneirophage.

Werewolf of Ancient Hunger

Vigilance, trample
Werewolf of Ancient Hunger's power and toughness are each equal to the total number of cards in all players' hands.
At the beginning of each upkeep, if a player cast two or more spells last turn, transform Werewolf of Ancient Hunger.

Sage of Ancient Lore

Sage of Ancient Lore's power and toughness are each equal to the number of cards in your hand.
When Sage of Ancient Lore enters, draw a card.
At the beginning of each upkeep, if no spells were cast last turn, transform Sage of Ancient Lore.

Sage of Ancient Lore // Werewolf of Ancient Hunger

Ivory Tower

At the beginning of your upkeep, you gain X life, where X is the number of cards in your hand minus 4.

Aether Tunnel

Enchant creature
Enchanted creature gets +1/+0 and can't be blocked.

Maro

Maro's power and toughness are each equal to the number of cards in your hand.

Key to the City

{T}, Discard a card: Up to one target creature can't be blocked this turn.
Whenever Key to the City becomes untapped, you may pay {2}. If you do, draw a card.

Thought Reflection

If you would draw a card, draw two cards instead.

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.

Jolrael, Voice of Zhalfir

At the beginning of combat on your turn, up to one target land you control becomes an X/X green and blue Bird creature with flying and haste until end of turn, where X is the number of cards in your hand. It's still a land.
Whenever a land creature you control deals combat damage to a player, draw a card.

Cloak of Mists

Enchant creature
Enchanted creature can't be blocked.

Tricks of the Trade

Enchant creature
Enchanted creature gets +2/+0 and can't be blocked.

Aqueous Form

Enchant creature
Enchanted creature can't be blocked.
Whenever enchanted creature attacks, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Duggan, Private Detective

Duggan's power and toughness are each equal to the number of cards in your hand.
Whenever Duggan enters or attacks, investigate.
The Most Important Punch in History — {1}{G}, {T}: Duggan deals damage equal to twice its power to another target creature. Activate only once.

Overbeing of Myth

Overbeing of Myth's power and toughness are each equal to the number of cards in your hand.
At the beginning of your draw step, draw an additional card.

Jolrael, Mwonvuli Recluse

Whenever you draw your second card each turn, create a 2/2 green Cat creature token.
{4}{G}{G}: Until end of turn, creatures you control have base power and toughness X/X, where X is the number of cards in your hand.

Masumaro, First to Live

Masumaro, First to Live's power and toughness are each equal to twice the number of cards in your hand.

Toothy, Imaginary Friend

Partner with Pir, Imaginative Rascal (When this creature enters, target player may put Pir into their hand from their library, then shuffle.)
Whenever you draw a card, put a +1/+1 counter on Toothy, Imaginary Friend.
When Toothy leaves the battlefield, draw a card for each +1/+1 counter on it.

Felix Five-Boots

Menace, ward {2}
If a creature you control dealing combat damage to a player causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

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.

Kagemaro, First to Suffer

Kagemaro, First to Suffer's power and toughness are each equal to the number of cards in your hand.
{B}, Sacrifice Kagemaro: All creatures get -X/-X until end of turn, where X is the number of cards in your hand.

Chasm Skulker

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

Lorescale Coatl

Whenever you draw a card, put a +1/+1 counter on Lorescale Coatl.

Starving Revenant

When Starving Revenant enters, surveil 2. Then for each card you put on top of your library, you draw a card and you lose 3 life.
Descend 8 — Whenever you draw a card, if there are eight or more permanent cards in your graveyard, target opponent loses 1 life and you gain 1 life.

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.

Inner Calm, Outer Strength

Target creature gets +X/+X until end of turn, where X is the number of cards in your hand.

Tishana, Voice of Thunder

Tishana, Voice of Thunder's power and toughness are each equal to the number of cards in your hand.
You have no maximum hand size.
When Tishana enters, draw a card for each creature you control.

Horizon Chimera

Flash
Flying, trample
Whenever you draw a card, you gain 1 life.

Nadir Kraken

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

Jace's Projection

Whenever you draw a card, put a +1/+1 counter on Jace's Projection.
{3}{U}: Put a loyalty counter on target Jace planeswalker.

Manifestation Sage

When Manifestation Sage enters, create a 0/0 green and blue Fractal creature token. Put X +1/+1 counters on it, where X is the number of cards in your hand.

Kagemaro's Clutch

Enchant creature
Enchanted creature gets -X/-X, where X is the number of cards in your hand.

Sturmgeist

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