Reliquary Tower

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

Arcane Signet

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

Mercurial Pretender

You may have this creature enter as a copy of a creature you control, except it has "{2}{U}{U}: Return this creature to its owner's hand."

Fierce Guardianship

If you control a commander, you may cast this spell without paying its mana cost.
Counter target noncreature spell.

Urza's Incubator

As this artifact enters, choose a creature type.
Creature spells of the chosen type cost {2} less to cast.

Queza, Augur of Agonies

Whenever you draw a card, target opponent loses 1 life and you gain 1 life.

Sakashima of a Thousand Faces

You may have Sakashima enter as a copy of another creature you control, except it has Sakashima's other abilities.
The "legend rule" doesn't apply to permanents you control.
Partner (You can have two commanders if both have partner.)

Mutated Cultist

Devoid (This card has no color.)
When you cast this spell, remove all counters from up to one target permanent or opponent. The next spell you cast this turn costs {1} less to cast for each counter removed this way.
Deathtouch

Trinket Mage

When this creature enters, you may search your library for an artifact card with mana value 1 or less, reveal that card, put it into your hand, then shuffle.

Cyclonic Rift

Return target nonland permanent you don't control to its owner's hand.
Overload {6}{U} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Mirror Image

You may have this creature enter as a copy of a creature you control.

Enlightened Tutor

Search your library for an artifact or enchantment card, reveal it, then shuffle and put that card on top.

The Millennium Calendar

Whenever you untap one or more permanents during your untap step, put that many time counters on The Millennium Calendar.
{2}, {T}: Double the number of time counters on The Millennium Calendar.
When there are 1,000 or more time counters on The Millennium Calendar, sacrifice it and each opponent loses 1,000 life.

Imperial Seal

Search your library for a card, then shuffle and put that card on top. You lose 2 life.

Glasspool Shore

Glasspool Mimic

You may have this creature enter as a copy of a creature you control, except it's a Shapeshifter Rogue in addition to its other types.

Glasspool Mimic // Glasspool Shore

Mana Drain

Counter target spell. At the beginning of your next main phase, add an amount of {C} equal to that spell's mana value.

Entomb

Search your library for a card, put that card into your graveyard, then shuffle.

Negate

Flesh Duplicate

You may have this creature enter as a copy of any creature on the battlefield, except it has vanishing 3 if that creature doesn't have vanishing. (A permanent with vanishing 3 enters with three time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)

Torment of Hailfire

Repeat the following process X times. Each opponent loses 3 life unless that player sacrifices a nonland permanent of their choice or discards a card.

Copycrook

You may have this creature enter as a copy of any creature on the battlefield, except it has "Whenever this creature attacks, it connives." (Draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on this creature.)

Clever Impersonator

You may have this creature enter as a copy of any nonland permanent on the battlefield.

Swan Song

Counter target enchantment, instant, or sorcery spell. Its controller creates a 2/2 blue Bird creature token with flying.

Reflecting Pool

{T}: Add one mana of any type that a land you control could produce.

Kindred Discovery

As this enchantment enters, choose a creature type.
Whenever a creature you control of the chosen type enters or attacks, draw a card.

Cavern of Souls

As this land enters, choose a creature type.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type, and that spell can't be countered.

Rhystic Study

Whenever an opponent casts a spell, you may draw a card unless that player pays {1}.

Exotic Orchard

{T}: Add one mana of any color that a land an opponent controls could produce.

An Offer You Can't Refuse

Counter target noncreature spell. Its controller creates two Treasure tokens. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")

Stunt Double

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

Clone

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

Sol Ring

Fabricate

Search your library for an artifact card, reveal it, put it into your hand, then shuffle.

Pirated Copy

You may have this creature enter as a copy of any creature on the battlefield, except it's a Pirate in addition to its other types and it has "Whenever this creature or another creature with the same name deals combat damage to a player, you draw a card."

Phantasmal Image

You may have this creature enter as a copy of any creature on the battlefield, except it's an Illusion in addition to its other types and it has "When this creature becomes the target of a spell or ability, sacrifice it."

Mystical Tutor

Search your library for an instant or sorcery card, reveal it, then shuffle and put that card on top.

Gigantoplasm

You may have this creature enter as a copy of any creature on the battlefield, except it has "{X}: This creature has base power and toughness X/X."

Island

Command Tower

Demonic Tutor

Search your library for a card, put that card into your hand, then shuffle.

Phyrexian Metamorph

({U/P} can be paid with either {U} or 2 life.)
You may have this creature enter as a copy of any artifact or creature on the battlefield, except it's an artifact in addition to its other types.

The One Ring

Indestructible
When The One Ring enters, if you cast it, you gain protection from everything until your next turn.
At the beginning of your upkeep, you lose 1 life for each burden counter on The One Ring.
{T}: Put a burden counter on The One Ring, then draw a card for each burden counter on The One Ring.

Counterspell

Visage Bandit

You may have this creature enter as a copy of a creature you control, except it's a Shapeshifter Rogue in addition to its other types.
Plot {2}{U} (You may pay {2}{U} and exile this card from your hand. Cast it as a sorcery on a later turn without paying its mana cost. Plot only as a sorcery.)

Jin-Gitaxias, Core Augur

Flash
At the beginning of your end step, draw seven cards.
Each opponent's maximum hand size is reduced by seven.

Personal Tutor

Search your library for a sorcery card, reveal it, then shuffle and put that card on top.

Force of Negation

If it's not your turn, you may exile a blue card from your hand rather than pay this spell's mana cost.
Counter target noncreature spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.