Counterspell

Mystical Tutor

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

Tezzeret the Seeker

+1: Untap up to two target artifacts.
−X: Search your library for an artifact card with mana value X or less, put it onto the battlefield, then shuffle.
−5: Artifacts you control become artifact creatures with base power and toughness 5/5 until end of turn.

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control.)
Equip {1}

Brainstorm

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

Polymorph

Destroy target creature. It can't be regenerated. Its controller reveals cards from the top of their library until they reveal a creature card. The player puts that card onto the battlefield, then shuffles all other cards revealed this way into their library.

An Offer You Can't Refuse

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

Urza's Saga

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Urza's Saga gains "{T}: Add {C}."
II — Urza's Saga gains "{2}, {T}: Create a 0/0 colorless Construct artifact creature token with 'This creature gets +1/+1 for each artifact you control.'"
III — Search your library for an artifact card with mana cost {0} or {1}, put it onto the battlefield, then shuffle.

Swan Song

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

Welding Jar

Sacrifice Welding Jar: Regenerate target artifact.

Thassa's Oracle

When Thassa's Oracle enters the battlefield, look at the top X cards of your library, where X is your devotion to blue. Put up to one of them on top of your library and the rest on the bottom of your library in a random order. If X is greater than or equal to the number of cards in your library, you win the game. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)

Walking Ballista

Walking Ballista enters the battlefield with X +1/+1 counters on it.
{4}: Put a +1/+1 counter on Walking Ballista.
Remove a +1/+1 counter from Walking Ballista: It deals 1 damage to any target.

Negate

Wurmcoil Engine

Deathtouch, lifelink
When Wurmcoil Engine dies, create a 3/3 colorless Phyrexian Wurm artifact creature token with deathtouch and a 3/3 colorless Phyrexian Wurm artifact creature token with lifelink.

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.

Mystic Remora

Cumulative upkeep {1} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
Whenever an opponent casts a noncreature spell, you may draw a card unless that player pays {4}.

Howling Mine

At the beginning of each player's draw step, if Howling Mine is untapped, that player draws an additional card.

Scroll Rack

{1}, {T}: Exile any number of cards from your hand face down. Put that many cards from the top of your library into your hand. Then look at the exiled cards and put them on top of your library in any order.

Spellseeker

When Spellseeker enters the battlefield, you may search your library for an instant or sorcery card with mana value 2 or less, reveal it, put it into your hand, then shuffle.

Solemn Simulacrum

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

Back to Basics

Nonbasic lands don't untap during their controllers' untap steps.

Karn, Scion of Urza

+1: Reveal the top two cards of your library. An opponent chooses one of them. Put that card into your hand and exile the other with a silver counter on it.
−1: Put a card you own with a silver counter on it from exile into your hand.
−2: Create a 0/0 colorless Construct artifact creature token with "This creature gets +1/+1 for each artifact you control."

Etherium Sculptor

Artifact spells you cast cost {1} less to cast.

Ponder

Look at the top three cards of your library, then put them back in any order. You may shuffle.
Draw a card.

Pithing Needle

As Pithing Needle enters the battlefield, choose a card name.
Activated abilities of sources with the chosen name can't be activated unless they're mana abilities.

Everflowing Chalice

Multikicker {2} (You may pay an additional {2} any number of times as you cast this spell.)
Everflowing Chalice enters the battlefield with a charge counter on it for each time it was kicked.
{T}: Add {C} for each charge counter on Everflowing Chalice.

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

Hullbreaker Horror

Flash
This spell can't be countered.
Whenever you cast a spell, choose up to one —
• Return target spell you don't control to its owner's hand.
• Return target nonland permanent to its owner's hand.

Blightsteel Colossus

Trample, infect, indestructible
If Blightsteel Colossus would be put into a graveyard from anywhere, reveal Blightsteel Colossus and shuffle it into its owner's library instead.

Isochron Scepter

Imprint — When Isochron Scepter enters the battlefield, you may exile an instant card with mana value 2 or less from your hand.
{2}, {T}: You may copy the exiled card. If you do, you may cast the copy without paying its mana cost.

Foundry Inspector

Force of Will

You may pay 1 life and exile a blue card from your hand rather than pay this spell's mana cost.
Counter target spell.

War Room

{T}: Add {C}.
{3}, {T}, Pay life equal to the number of colors in your commanders' color identity: Draw a card.

Rhystic Study

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

Kasmina's Transmutation

Enchant creature
Enchanted creature loses all abilities and has base power and toughness 1/1.

Gitaxian Probe

({U/P} can be paid with either {U} or 2 life.)
Look at target player's hand.
Draw a card.

Vedalken Archmage

Whenever you cast an artifact spell, draw a card.

Academy Ruins

{T}: Add {C}.
{1}{U}, {T}: Put target artifact card from your graveyard on top of your library.

The Reality Chip

You may look at the top card of your library any time.
As long as The Reality Chip is attached to a creature, you may play lands and cast spells from the top of your library.
Reconfigure {2}{U} ({2}{U}: Attach to target creature you control; or unattach from a creature. Reconfigure only as a sorcery. While attached, this isn't a creature.)

Fierce Guardianship

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

Remote Isle

Remote Isle enters the battlefield tapped.
{T}: Add {U}.
Cycling {2} ({2}, Discard this card: Draw a card.)

Memnarch

{1}{U}{U}: Target permanent becomes an artifact in addition to its other types. (This effect lasts indefinitely.)
{3}{U}: Gain control of target artifact. (This effect lasts indefinitely.)

Urza, Lord High Artificer

When Urza, Lord High Artificer enters the battlefield, create a 0/0 colorless Construct artifact creature token with "This creature gets +1/+1 for each artifact you control."
Tap an untapped artifact you control: Add {U}.
{5}: Shuffle your library, then exile the top card. Until end of turn, you may play that card without paying its mana cost.

Tribute Mage

When Tribute Mage enters the battlefield, you may search your library for an artifact card with mana value 2, reveal that card, put it into your hand, then shuffle.

Arcane Denial

Counter target spell. Its controller may draw up to two cards at the beginning of the next turn's upkeep.
You draw a card at the beginning of the next turn's upkeep.

Ornithopter

Blast Zone

Blast Zone enters the battlefield with a charge counter on it.
{T}: Add {C}.
{X}{X}, {T}: Put X charge counters on Blast Zone.
{3}, {T}, Sacrifice Blast Zone: Destroy each nonland permanent with mana value equal to the number of charge counters on Blast Zone.

Urza's Bauble

{T}, Sacrifice Urza's Bauble: Look at a card at random in target player's hand. You draw a card at the beginning of the next turn's upkeep.

Merchant Scroll

Search your library for a blue instant card, reveal that card, put it into your hand, then shuffle.

Reshape

As an additional cost to cast this spell, sacrifice an artifact.
Search your library for an artifact card with mana value X or less, put it onto the battlefield, then shuffle.

Fabricate

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

Static Orb

As long as Static Orb is untapped, players can't untap more than two permanents during their untap steps.

The Mycosynth Gardens

{T}: Add {C}.
{1}, {T}: Add one mana of any color.
{X}, {T}: The Mycosynth Gardens becomes a copy of target nontoken artifact you control with mana value X.

Halimar Depths

Halimar Depths enters the battlefield tapped.
When Halimar Depths enters the battlefield, look at the top three cards of your library, then put them back in any order.
{T}: Add {U}.

Portent

Look at the top three cards of target player's library, then put them back in any order. You may have that player shuffle.
Draw a card at the beginning of the next turn's upkeep.

Spellskite

{U/P}: Change a target of target spell or ability to Spellskite. ({U/P} can be paid with either {U} or 2 life.)

Sculpting Steel

You may have Sculpting Steel enter the battlefield as a copy of any artifact on the battlefield.

Otawara, Soaring City

{T}: Add {U}.
Channel — {3}{U}, Discard Otawara, Soaring City: Return target artifact, creature, enchantment, or planeswalker to its owner's hand. This ability costs {1} less to activate for each legendary creature you control.

Winter Orb

As long as Winter Orb is untapped, players can't untap more than one land during their untap steps.

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.")

Spellbook

Sol Ring

Jeweled Lotus

{T}, Sacrifice Jeweled Lotus: Add three mana of any one color. Spend this mana only to cast your commander.

Imposter Mech

You may have Imposter Mech enter the battlefield as a copy of a creature an opponent controls, except it's a Vehicle artifact with crew 3 and it loses all other card types.
Crew 3

Darksteel Citadel

Emry, Lurker of the Loch

This spell costs {1} less to cast for each artifact you control.
When Emry, Lurker of the Loch enters the battlefield, mill four cards.
{T}: Choose target artifact card in your graveyard. You may cast that card this turn. (You still pay its costs. Timing rules still apply.)

Whir of Invention

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
Search your library for an artifact card with mana value X or less, put it onto the battlefield, then shuffle.

Thought Monitor

Affinity for artifacts
Flying
When Thought Monitor enters the battlefield, draw two cards.

Sensei's Divining Top

{1}: Look at the top three cards of your library, then put them back in any order.
{T}: Draw a card, then put Sensei's Divining Top on top of its owner's library.