Overpowering Attack

Freerunning {2}{R} (You may cast this spell for its freerunning cost if you dealt combat damage to a player this turn with an Assassin or commander.)
Untap all creatures you control that attacked this turn. If it's your main phase, there is an additional combat phase after this phase, followed by an additional main phase.

Defense Grid

Each spell costs {3} more to cast except during its controller's turn.

Arcane Signet

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

Red Elemental Blast

Choose one —
• Counter target blue spell.
• Destroy target blue permanent.

Lizard Blades

Double strike
Equipped creature has double strike.
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.)

Final Fortune

Take an extra turn after this one. At the beginning of that turn's end step, you lose the game.

Imperial Recruiter

When Imperial Recruiter enters, search your library for a creature card with power 2 or less, reveal it, put it into your hand, then shuffle.

Shiny Impetus

Enchant creature
Enchanted creature gets +2/+2 and is goaded. (It attacks each combat if able and attacks a player other than you if able.)
Whenever enchanted creature attacks, you create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

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}

Gamble

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

Tibalt's Trickery

Counter target spell. Choose 1, 2, or 3 at random. Its controller mills that many cards, then exiles cards from the top of their library until they exile a nonland card with a different name than that spell. They may cast that card without paying its mana cost. Then they put the exiled cards on the bottom of their library in a random order.

Chaos Warp

The owner of target permanent shuffles it into their library, then reveals the top card of their library. If it's a permanent card, they put it onto the battlefield.

Alexios, Deimos of Kosmos

Trample
Alexios, Deimos of Kosmos 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.

Sword of Truth and Justice

Equipped creature gets +2/+2 and has protection from white and from blue.
Whenever equipped creature deals combat damage to a player, put a +1/+1 counter on a creature you control, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)
Equip {2}

Arena of Glory

Arena of Glory enters tapped unless you control a Mountain.
{T}: Add {R}.
{R}, {T}, Exert Arena of Glory: Add {R}{R}. If that mana is spent on a creature spell, it gains haste until end of turn. (An exerted permanent won't untap during your next untap step.)

Silent Arbiter

No more than one creature can attack each combat.
No more than one creature can block each combat.

Bazaar of Baghdad

{T}: Draw two cards, then discard three cards.

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}

Ragavan, Nimble Pilferer

Whenever Ragavan, Nimble Pilferer deals combat damage to a player, create a Treasure token and exile the top card of that player's library. Until end of turn, you may cast that card.
Dash {1}{R} (You may cast this spell for its dash cost. If you do, it gains haste, and it's returned from the battlefield to its owner's hand at the beginning of the next end step.)

Blasphemous Act

This spell costs {1} less to cast for each creature on the battlefield.
Blasphemous Act deals 13 damage to each creature.

Ruby Medallion

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

Brass Squire

{T}: Attach target Equipment you control to target creature you control.

The Sound of Drums

Enchant creature
Enchanted creature is goaded.
If enchanted creature would deal combat damage to a permanent or player, it deals double that damage instead.
{2}{R}: Return The Sound of Drums from your graveyard to your hand.

Brash Taunter

Indestructible
Whenever Brash Taunter is dealt damage, it deals that much damage to target opponent.
{2}{R}, {T}: Brash Taunter fights another target creature.

Cliffhaven Kitesail

When Cliffhaven Kitesail enters, attach it to target creature you control.
Equipped creature has flying.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Pyroblast

Choose one —
• Counter target spell if it's blue.
• Destroy target permanent if it's blue.

Brotherhood Regalia

Equipped creature has ward {2}, is an Assassin in addition to its other types, and can't be blocked.
Equip legendary creature {1}
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

Iron Myr

Agitator Ant

At the beginning of your end step, each player may put two +1/+1 counters on a creature they control. Goad each creature that had counters put on it this way. (Until your next turn, those creatures attack each combat if able and attack a player other than you if able.)

Unleash Fury

Double the power of target creature until end of turn.

Winter Moon

Players can't untap more than one nonbasic land during their untap steps.

Whispersilk Cloak

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

Destructive Urge

Enchant creature
Whenever enchanted creature deals combat damage to a player, that player sacrifices a land.

Bothersome Quasit

Menace
Goaded creatures your opponents control can't block.
Whenever you cast a noncreature spell, goad target creature an opponent controls. (Until your next turn, that creature attacks each combat if able and attacks a player other than you if able.)

Temur Battle Rage

Target creature gains double strike until end of turn.
Ferocious — That creature also gains trample until end of turn if you control a creature with power 4 or greater.

Grafdigger's Cage

Creature cards in graveyards and libraries can't enter the battlefield.
Players can't cast spells from graveyards or libraries.

Inventors' Fair

At the beginning of your upkeep, if you control three or more artifacts, you gain 1 life.
{T}: Add {C}.
{4}, {T}, Sacrifice Inventors' Fair: Search your library for an artifact card, reveal it, put it into your hand, then shuffle. Activate only if you control three or more artifacts.

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.

Lightning Greaves

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

Mjölnir, Storm Hammer

When Mjölnir enters, attach it to target legendary creature you control.
Whenever equipped creature attacks, tap target creature defending player controls and put a stun counter on it. Then Mjölnir deals damage to each opponent equal to the number of tapped creatures that opponent controls.
Equip {4}

Deflecting Swat

If you control a commander, you may cast this spell without paying its mana cost.
You may choose new targets for target spell or ability.

Excalibur, Sword of Eden

This spell costs {X} less to cast, where X is the total mana value of historic permanents you control. (Artifacts, legendaries, and Sagas are historic.)
Equipped creature gets +10/+0 and has vigilance.
Equip legendary creature {2}

Mountain

Fire Diamond

Fire Diamond enters tapped.
{T}: Add {R}.

Bolt Bend

This spell costs {3} less to cast if you control a creature with power 4 or greater.
Change the target of target spell or ability with a single target.

Jeweled Lotus

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

Kediss, Emberclaw Familiar

Whenever a commander you control deals combat damage to an opponent, it deals that much damage to each other opponent.
Partner (You can have two commanders if both have partner.)

Blackblade Reforged

Equipped creature gets +1/+1 for each land you control.
Equip legendary creature {3}
Equip {7}

Ornithopter of Paradise

Towering Viewpoint

Defender, reach
Leap of Faith — {3}: Target creature gains flying until end of turn.

Silver Shroud Costume

Flash
When Silver Shroud Costume enters, attach it to target creature you control. That creature gains shroud until end of turn. (It can't be the target of spells or abilities.)
Equipped creature can't be blocked.
Equip {3}

Swiftfoot Boots

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

Vexing Bauble

Whenever a player casts a spell, if no mana was spent to cast it, counter that spell.
{1}, {T}, Sacrifice Vexing Bauble: Draw a card.

Jeska's Will

Choose one. If you control a commander as you cast this spell, you may choose both instead.
• Add {R} for each card in target opponent's hand.
• Exile the top three cards of your library. You may play them this turn.

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice Mind Stone: Draw a card.

Sol Ring

Sunspine Lynx

Players can't gain life.
Damage can't be prevented.
When Sunspine Lynx enters, it deals damage to each player equal to the number of nonbasic lands that player controls.

Sword of Light and Shadow

Equipped creature gets +2/+2 and has protection from white and from black.
Whenever equipped creature deals combat damage to a player, you gain 3 life and you may return up to one target creature card from your graveyard to your hand.
Equip {2}

Volcanic Fissure

As Volcanic Fissure enters, you may pay 3 life. If you don't, it enters tapped.
{T}: Add {R}.

Sundering Eruption

Destroy target land. Its controller may search their library for a basic land card, put it onto the battlefield tapped, then shuffle. Creatures without flying can't block this turn.

Sundering Eruption // Volcanic Fissure

Mana Crypt

At the beginning of your upkeep, flip a coin. If you lose the flip, Mana Crypt deals 3 damage to you.
{T}: Add {C}{C}.

Mithril Coat

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

Goblin Engineer

When Goblin Engineer enters, you may search your library for an artifact card, put it into your graveyard, then shuffle.
{R}, {T}, Sacrifice an artifact: Return target artifact card with mana value 3 or less from your graveyard to the battlefield.

Komainu Battle Armor

Menace
Equipped creature gets +2/+2 and has menace.
Whenever Komainu Battle Armor 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.)

Grim Monolith

Grim Monolith doesn't untap during your untap step.
{T}: Add {C}{C}{C}.
{4}: Untap Grim Monolith.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Champion's Helm

Equipped creature gets +2/+2.
As long as equipped creature is legendary, it has hexproof. (It can't be the target of spells or abilities your opponents control.)
Equip {1}

Seething Song

Jeska, Thrice Reborn

Jeska, Thrice Reborn enters with a loyalty counter on her for each time you've cast a commander from the command zone this game.
0: Choose target creature. Until your next turn, if that creature would deal combat damage to one of your opponents, it deals triple that damage to that player instead.
−X: Jeska, Thrice Reborn deals X damage to each of up to three targets.
Jeska, Thrice Reborn can be your commander.
Partner

Lotus Petal

{T}, Sacrifice Lotus Petal: Add one mana of any color.

Pyretic Ritual

Mox Amber

{T}: Add one mana of any color among legendary creatures and planeswalkers you control.

Chainsaw

When Chainsaw enters, it deals 3 damage to up to one target creature.
Whenever one or more creatures die, put a rev counter on Chainsaw.
Equipped creature gets +X/+0, where X is the number of rev counters on Chainsaw.
Equip {3}

Return the Favor

Spree (Choose one or more additional costs.)
+ {1} — Copy target instant spell, sorcery spell, activated ability, or triggered ability. You may choose new targets for the copy.
+ {1} — Change the target of target spell or ability with a single target.

Sword of Fire and Ice

Equipped creature gets +2/+2 and has protection from red and from blue.
Whenever equipped creature deals combat damage to a player, Sword of Fire and Ice deals 2 damage to any target and you draw a card.
Equip {2}

Commander's Plate

Equipped creature gets +3/+3 and has protection from each color that's not in your commander's color identity.
Equip commander {3}
Equip {5}