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.

Nimble Obstructionist

Flash
Flying
Cycling {2}{U} ({2}{U}, Discard this card: Draw a card.)
When you cycle Nimble Obstructionist, counter target activated or triggered ability you don't control.

Praetor's Counsel

Return all cards from your graveyard to your hand. Exile Praetor's Counsel. You have no maximum hand size for the rest of the game.

Thryx, the Sudden Storm

Flash
Flying
Spells you cast with mana value 5 or greater cost {1} less to cast and can't be countered.

Sea Gate, Reborn

As Sea Gate, Reborn enters the battlefield, you may pay 3 life. If you don't, it enters the battlefield tapped.
{T}: Add {U}.

Sea Gate Restoration

Draw cards equal to the number of cards in your hand plus one. You have no maximum hand size for the rest of the game.

Sea Gate Restoration // Sea Gate, Reborn

Teferi, Mage of Zhalfir

Flash
Creature cards you own that aren't on the battlefield have flash.
Each opponent can cast spells only any time they could cast a sorcery.

Sweet-Gum Recluse

Flash
Cascade
Reach
When Sweet-Gum Recluse enters the battlefield, put three +1/+1 counters on each of any number of target creatures that entered the battlefield this turn.

Tidal Barracuda

Any player may cast spells as though they had flash.
Your opponents can't cast spells during your turn.

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.

Library of Leng

You have no maximum hand size.
If an effect causes you to discard a card, discard it, but you may put it on top of your library instead of into your graveyard.

Plaxmanta

Flash
When Plaxmanta enters the battlefield, creatures you control gain shroud until end of turn. (They can't be the targets of spells or abilities.)
When Plaxmanta enters the battlefield, sacrifice it unless {G} was spent to cast it.

Spellbook

Thought Vessel

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

Bounding Krasis

Flash (You may cast this spell any time you could cast an instant.)
When Bounding Krasis enters the battlefield, you may tap or untap target creature.

Sakashima's Protege

Flash
Cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom of your library in a random order.)
You may have Sakashima's Protege enter the battlefield as a copy of any permanent that entered the battlefield this turn.

Venser, Shaper Savant

Flash
When Venser, Shaper Savant enters the battlefield, return target spell or permanent to its owner's hand.

Torrential Gearhulk

Flash
When Torrential Gearhulk enters the battlefield, you may cast target instant card from your graveyard without paying its mana cost. If that spell would be put into your graveyard, exile it instead.

Kruphix, God of Horizons

Indestructible
As long as your devotion to green and blue is less than seven, Kruphix isn't a creature.
You have no maximum hand size.
If you would lose unspent mana, that mana becomes colorless instead.

The Magic Mirror

This spell costs {1} less to cast for each instant and sorcery card in your graveyard.
You have no maximum hand size.
At the beginning of your upkeep, put a knowledge counter on The Magic Mirror, then draw a card for each knowledge counter on The Magic Mirror.

Breaching Hippocamp

Flash (You may cast this spell any time you could cast an instant.)
When Breaching Hippocamp enters the battlefield, untap another target creature you control.

Pearl Lake Ancient

Flash
This spell can't be countered.
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Return three lands you control to their owner's hand: Return Pearl Lake Ancient to its owner's hand.

Finale of Revelation

Draw X cards. If X is 10 or more, instead shuffle your graveyard into your library, draw X cards, untap up to five lands, and you have no maximum hand size for the rest of the game.
Exile Finale of Revelation.

Sentinel of the Pearl Trident

Flash
When Sentinel of the Pearl Trident enters the battlefield, you may exile target historic permanent you control. If you do, return that card to the battlefield under its owner's control at the beginning of the next end step. (Artifacts, legendaries, and Sagas are historic.)

Deceiver Exarch

Flash (You may cast this spell any time you could cast an instant.)
When Deceiver Exarch enters the battlefield, choose one —
• Untap target permanent you control.
• Tap target permanent an opponent controls.

Pestermite

Flash
Flying
When Pestermite enters the battlefield, you may tap or untap target permanent.

Nezahal, Primal Tide

This spell can't be countered.
You have no maximum hand size.
Whenever an opponent casts a noncreature spell, draw a card.
Discard three cards: Exile Nezahal, Primal Tide. Return it to the battlefield tapped under its owner's control at the beginning of the next end step.

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 Body of Knowledge is dealt damage, draw that many cards.

Voidmage Husher

Flash (You may cast this spell any time you could cast an instant.)
When Voidmage Husher enters the battlefield, counter target activated ability. (Mana abilities can't be targeted.)
Whenever you cast a spell, you may return Voidmage Husher to its owner's hand.

Petty Theft

Return target nonland permanent an opponent controls to its owner's hand.

Brazen Borrower

Flash
Flying
Brazen Borrower can block only creatures with flying.

Brazen Borrower // Petty Theft

Spectral Sailor

Flash (You may cast this spell any time you could cast an instant.)
Flying
{3}{U}: Draw a card.

Fleetfeather Cockatrice

Flash (You may cast this spell any time you could cast an instant.)
Flying, deathtouch
{5}{G}{U}: Monstrosity 3. (If this creature isn't monstrous, put three +1/+1 counters on it and it becomes monstrous.)