Trouble in Pairs

If an opponent would begin an extra turn, that player skips that turn instead.
Whenever an opponent attacks you with two or more creatures, draws their second card each turn, or casts their second spell each turn, you draw a card.

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Command Tower

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

Abrade

Choose one —
• Abrade deals 3 damage to target creature.
• Destroy target artifact.

Lion Sash

{W}: Exile target card from a graveyard. If it was a permanent card, put a +1/+1 counter on this permanent.
Equipped creature gets +1/+1 for each +1/+1 counter on this Equipment.
Reconfigure {2} ({2}: Attach to target creature you control; or unattach from a creature. Reconfigure only as a sorcery. While attached, this isn't a creature.)

Buried Ruin

{T}: Add {C}.
{2}, {T}, Sacrifice this land: Return target artifact card from your graveyard to your hand.

Raphael, the Muscle

Double all damage that creatures you control with counters on them would deal.
When Raphael enters, create a Mutagen token.
Partner—Character select (You can have two commanders if both have this ability.)

Reconnaissance

{0}: Remove target attacking creature you control from combat and untap it. (If you activate during end of combat, the creature will untap after it deals combat damage.)

Alexios, Deimos of Kosmos

Trample
Alexios attacks each combat if able, can't be sacrificed, and can't attack its owner.
At the beginning of each player's upkeep, that player gains control of Alexios, untaps it, and puts a +1/+1 counter on it. It gains haste until end of turn.

Commander's Sphere

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

Bladehold War-Whip

For Mirrodin! (When this Equipment enters, create a 2/2 red Rebel creature token, then attach this to it.)
Equip abilities you activate of other Equipment cost {1} less to activate.
Equipped creature has double strike.
Equip {3}{R}{W}

Puresteel Paladin

Whenever an Equipment you control enters, you may draw a card.
Metalcraft — Equipment you control have equip {0} as long as you control three or more artifacts.

Sol Ring

Hammer of Nazahn

Whenever Hammer of Nazahn or another Equipment you control enters, you may attach that Equipment to target creature you control.
Equipped creature gets +2/+0 and has indestructible.
Equip {4}

Mountain

Brave the Sands

Creatures you control have vigilance.
Each creature you control can block an additional creature each combat.

Inspiring Statuary

Nonartifact spells you cast have improvise. (Your artifacts can help cast those spells. Each artifact you tap after you're done activating mana abilities pays for {1}.)

Sephiroth, Fallen Hero

Jenova Cells — Whenever Sephiroth attacks, you may put a cell counter on target creature. Until end of turn, each modified creature you control has base power and toughness 7/5. (Equipment, Auras you control, and counters are modifications.)
The Reunion — {3}, Sacrifice a modified creature: Return this card from your graveyard to the battlefield tapped.

Caretaker's Talent

(Gain the next level as a sorcery to add its ability.)
Whenever one or more tokens you control enter, draw a card. This ability triggers only once each turn.
{W}: Level 2
When this Class becomes level 2, create a token that's a copy of target token you control.
{3}{W}: Level 3
Creature tokens you control get +2/+2.

Alpine Meadow

({T}: Add {R} or {W}.)
This land enters tapped.

Flawless Maneuver

If you control a commander, you may cast this spell without paying its mana cost.
Creatures you control gain indestructible until end of turn.

Codsworth, Handy Helper

Commanders you control have ward {2}.
{T}: Add {W}{W}. Spend this mana only to cast Aura and/or Equipment spells.
{T}: Attach target Aura or Equipment you control to target creature you control. Activate only as a sorcery.

Rustvale Bridge

This land enters tapped.
Indestructible
{T}: Add {R} or {W}.

Chain Reaction

Chain Reaction deals X damage to each creature, where X is the number of creatures on the battlefield.

Sunhome, Fortress of the Legion

{T}: Add {C}.
{2}{R}{W}, {T}: Target creature gains double strike until end of turn.

Open the Armory

Search your library for an Aura or Equipment card, reveal it, put it into your hand, then shuffle.

Bladegraft Aspirant

Menace
Equipment spells you cast cost {1} less to cast.
Activated abilities of Equipment you control that target this creature cost {1} less to activate.

Path to Exile

Exile target creature. Its controller may search their library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Exotic Orchard

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

Arcane Signet

Ghost Quarter

{T}: Add {C}.
{T}, Sacrifice this land: Destroy target land. Its controller may search their library for a basic land card, put it onto the battlefield, then shuffle.

Buster Sword

Equipped creature gets +3/+2.
Whenever equipped creature deals combat damage to a player, draw a card, then you may cast a spell from your hand with mana value less than or equal to that damage without paying its mana cost.
Equip {2}

Talisman of Conviction

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

Abraded Bluffs

This land enters tapped.
When this land enters, it deals 1 damage to target opponent.
{T}: Add {R} or {W}.

The Spear of Leonidas

Whenever equipped creature attacks, choose one —
• Bull Rush — It gains double strike until end of turn.
• Summon — Create Phobos, a legendary 3/2 red Horse creature token.
• Revelation — Discard two cards, then draw two cards.
Equip {2}

Stone Quarry

This land enters tapped.
{T}: Add {R} or {W}.

Red Mage's Rapier

Job select (When this Equipment enters, create a 1/1 colorless Hero creature token, then attach this to it.)
Equipped creature has "Whenever you cast a noncreature spell, this creature gets +2/+0 until end of turn" and is a Wizard in addition to its other types.
Equip {3}

Bureau Headmaster

Equipment spells you cast cost {1} less to cast.
Equip abilities you activate cost {1} less to activate.

Stoneforge Mystic

When this creature enters, you may search your library for an Equipment card, reveal it, put it into your hand, then shuffle.
{1}{W}, {T}: You may put an Equipment card from your hand onto the battlefield.

Astor, Bearer of Blades

When Astor enters, look at the top seven cards of your library. You may reveal an Equipment or Vehicle card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.
Equipment you control have equip {1}.
Vehicles you control have crew 1.

Slicer, High-Speed Antagonist

Living metal (During your turn, this Vehicle is also a creature.)
First strike, haste
Whenever Slicer deals combat damage to a player, convert it at end of combat.

Slicer, Hired Muscle

More Than Meets the Eye {2}{R} (You may cast this card converted for {2}{R}.)
Double strike, haste
At the beginning of each opponent's upkeep, you may have that player gain control of Slicer until end of turn. If you do, untap Slicer, goad it, and it can't be sacrificed this turn. If you don't, convert it.

Slicer, Hired Muscle // Slicer, High-Speed Antagonist

Tocasia's Welcome

Whenever one or more creatures you control with mana value 3 or less enter, draw a card. This ability triggers only once each turn.

Shadowspear

Equipped creature gets +1/+1 and has trample and lifelink.
{1}: Permanents your opponents control lose hexproof and indestructible until end of turn.
Equip {2}

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

White Mage's Staff

Job select (When this Equipment enters, create a 1/1 colorless Hero creature token, then attach this to it.)
Equipped creature gets +1/+1, has "Whenever this creature attacks, you gain 1 life," and is a Cleric in addition to its other types.
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

Rising of the Day

Creatures you control have haste.
Legendary creatures you control get +1/+0.

Glimmer Lens

For Mirrodin! (When this Equipment enters, create a 2/2 red Rebel creature token, then attach this to it.)
Whenever equipped creature and at least one other creature attack, draw a card.
Equip {1}{W}

Destroy Evil

Choose one —
• Destroy target creature with toughness 4 or greater.
• Destroy target enchantment.

Freya Crescent

Jump — During your turn, Freya Crescent has flying.
{T}: Add {R}. Spend this mana only to cast an Equipment spell or activate an equip ability.

Battlefield Forge

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

Cloud, Midgar Mercenary

When Cloud enters, search your library for an Equipment card, reveal it, put it into your hand, then shuffle.
As long as Cloud is equipped, if an ability of Cloud or an Equipment attached to it triggers, that ability triggers an additional time.

Firion, Wild Rose Warrior

Equipped creatures you control have haste.
Whenever a nontoken Equipment you control enters, create a token that's a copy of it, except it has "This Equipment's equip abilities cost {2} less to activate." Sacrifice that token at the beginning of the next upkeep.

Hexgold Halberd

For Mirrodin! (When this Equipment enters, create a 2/2 red Rebel creature token, then attach this to it.)
During your turn, equipped creature has first strike and trample.
Equip {2}{R}

Smuggler's Share

At the beginning of each end step, draw a card for each opponent who drew two or more cards this turn, then create a Treasure token for each opponent who had two or more lands enter the battlefield under their control this turn.

Welcoming Vampire

Flying
Whenever one or more other creatures you control with power 2 or less enter, draw a card. This ability triggers only once each turn.

Temple of Triumph

This land enters tapped.
When this land enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{T}: Add {R} or {W}.

Wind-Scarred Crag

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {R} or {W}.

Citadel Gate

This land enters tapped.
As this land enters, choose a color other than white.
{T}: Add {W} or one mana of the chosen color.

Worn Powerstone

This artifact enters tapped.
{T}: Add {C}{C}.

Giggling Skitterspike

Indestructible
Whenever this creature attacks, blocks, or becomes the target of a spell, it deals damage equal to its power to each opponent.
{5}: Monstrosity 5. (If this creature isn't monstrous, put five +1/+1 counters on it and it becomes monstrous.)

Plains

Liquimetal Torque

{T}: Add {C}.
{T}: Target nonland permanent becomes an artifact in addition to its other types until end of turn.

Machinist's Arsenal

Job select (When this Equipment enters, create a 1/1 colorless Hero creature token, then attach this to it.)
Equipped creature gets +2/+2 for each artifact you control and is an Artificer in addition to its other types.
Machina — Equip {4} ({4}: Attach to target creature you control. Equip only as a sorcery.)

Monk's Fist

Job select (When this Equipment enters, create a 1/1 colorless Hero creature token, then attach this to it.)
Equipped creature gets +1/+0 and is a Monk in addition to its other types.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Komainu Battle Armor

Menace
Equipped creature gets +2/+2 and has menace.
Whenever this creature or equipped creature deals combat damage to a player, goad each creature that player controls.
Reconfigure {4} ({4}: Attach to target creature you control; or unattach from a creature. Reconfigure only as a sorcery. While attached, this isn't a creature.)

Sacred Foundry

({T}: Add {R} or {W}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

Reckless Impulse

Exile the top two cards of your library. Until the end of your next turn, you may play those cards.

Kratos, God of War

Double strike
All creatures have haste.
At the beginning of each player's end step, Kratos deals damage to that player equal to the number of creatures that player controls that didn't attack this turn.

Cliffgate

This land enters tapped.
As this land enters, choose a color other than red.
{T}: Add {R} or one mana of the chosen color.

Birthright Boon

Kellan, the Fae-Blooded

Double strike
Other creatures you control get +1/+0 for each Aura and Equipment attached to Kellan.

Kellan, the Fae-Blooded // Birthright Boon

Clifftop Retreat

This land enters tapped unless you control a Mountain or a Plains.
{T}: Add {R} or {W}.

Fighter Class

(Gain the next level as a sorcery to add its ability.)
When this Class enters, search your library for an Equipment card, reveal it, put it into your hand, then shuffle.
{1}{R}{W}: Level 2
Equip abilities you activate cost {2} less to activate.
{3}{R}{W}: Level 3
Whenever a creature you control attacks, up to one target creature blocks it this combat if able.

Thriving Bluff

This land enters tapped. As it enters, choose a color other than red.
{T}: Add {R} or one mana of the chosen color.

Cathars' Crusade

Whenever a creature you control enters, put a +1/+1 counter on each creature you control.

Boros Guildgate

Nettlecyst

Living weapon (When this Equipment enters, create a 0/0 black Phyrexian Germ creature token, then attach this to it.)
Equipped creature gets +1/+1 for each artifact and/or enchantment you control.
Equip {2}

Kassandra, Eagle Bearer

Haste
When Kassandra enters, search your graveyard, hand, and library for a card named The Spear of Leonidas, put it onto the battlefield, then shuffle.
Whenever a creature you control with a legendary Equipment attached to it deals combat damage to a player, draw a card.

Mithril Coat

Flash
Indestructible
When Mithril Coat enters, attach it to target legendary creature you control.
Equipped creature has indestructible.
Equip {3}

Path of Ancestry

This land enters tapped.
{T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Samurai's Katana

Job select (When this Equipment enters, create a 1/1 colorless Hero creature token, then attach this to it.)
Equipped creature gets +2/+2, has trample and haste, and is a Samurai in addition to its other types.
Murasame — Equip {5}

Austere Command

Choose two —
• Destroy all artifacts.
• Destroy all enchantments.
• Destroy all creatures with mana value 3 or less.
• Destroy all creatures with mana value 4 or greater.

Sram, Senior Edificer

Whenever you cast an Aura, Equipment, or Vehicle spell, draw a card.

Wrenn's Resolve

Urza's Saga

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — This Saga gains "{T}: Add {C}."
II — This Saga gains "{2}, {T}: Create a 0/0 colorless Construct artifact creature token with 'This token 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.