Command the Dreadhorde

Choose any number of target creature and/or planeswalker cards in graveyards. Command the Dreadhorde deals damage to you equal to the total mana value of those cards. Put them onto the battlefield under your control.

Entering

Put a creature card from a graveyard onto the battlefield under your control. It gains haste until end of turn.
Fuse (You may cast one or both halves of this card from your hand.)

Breaking

Target player mills eight cards.
Fuse (You may cast one or both halves of this card from your hand.)

Breaking // Entering

Gruul Signet

Haunting Imitation

Each player reveals the top card of their library. For each creature card revealed this way, create a token that's a copy of that card, except it's 1/1, it's a Spirit in addition to its other types, and it has flying. If no creature cards were revealed this way, return Haunting Imitation to its owner's hand.

Voracious Reader

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Instant and sorcery spells you cast cost {1} less to cast.

Curious Homunculus

{T}: Add {C}. Spend this mana only to cast an instant or sorcery spell.
At the beginning of your upkeep, if there are three or more instant and/or sorcery cards in your graveyard, transform Curious Homunculus.

Curious Homunculus // Voracious Reader

Arcane Signet

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

Battlefield Thaumaturge

Each instant and sorcery spell you cast costs {1} less to cast for each creature it targets.
Heroic — Whenever you cast a spell that targets Battlefield Thaumaturge, Battlefield Thaumaturge gains hexproof until end of turn.

Dragonskull Summit

Dragonskull Summit enters tapped unless you control a Swamp or a Mountain.
{T}: Add {B} or {R}.

Azorius Signet

Rakdos Signet

Smoldering Marsh

({T}: Add {B} or {R}.)
Smoldering Marsh enters tapped unless you control two or more basic lands.

Glacial Fortress

Glacial Fortress enters tapped unless you control a Plains or an Island.
{T}: Add {W} or {U}.

Mocking Sprite

Flying
Instant and sorcery spells you cast cost {1} less to cast.

Canopy Vista

({T}: Add {G} or {W}.)
Canopy Vista enters tapped unless you control two or more basic lands.

Spitting Image

Create a token that's a copy of target creature.
Retrace (You may cast this card from your graveyard by discarding a land card in addition to paying its other costs.)

Telemin Performance

Target opponent reveals cards from the top of their library until they reveal a creature card. That player puts all noncreature cards revealed this way into their graveyard, then you put the creature card onto the battlefield under your control.

Assassin's Trophy

Destroy target permanent an opponent controls. Its controller may search their library for a basic land card, put it onto the battlefield, then shuffle.

Sulfur Falls

Sulfur Falls enters tapped unless you control an Island or a Mountain.
{T}: Add {U} or {R}.

Mythos of Illuna

Create a token that's a copy of target permanent. If {R}{G} was spent to cast this spell, instead create a token that's a copy of that permanent, except the token has "When this permanent enters, if it's a creature, it fights up to one target creature you don't control."

Codie, Vociferous Codex

You can't cast permanent spells.
{4}, {T}: Add {W}{U}{B}{R}{G}. When you next cast a spell this turn, exile cards from the top of your library until you exile an instant or sorcery card with lesser mana value. Until end of turn, you may cast that card without paying its mana cost. Put each other card exiled this way on the bottom of your library in a random order.

Grave Upheaval

Put target creature card from a graveyard onto the battlefield under your control. It gains haste.
Basic landcycling {2} ({2}, Discard this card: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.)

Golgari Signet

Selesnya Signet

Punishment

Destroy each artifact, creature, and enchantment with mana value X.

Crime

Put target creature or enchantment card from an opponent's graveyard onto the battlefield under your control.

Crime // Punishment

Emergent Sequence

Search your library for a basic land card, put it onto the battlefield tapped, then shuffle. That land becomes a 0/0 green and blue Fractal creature that's still a land. Put a +1/+1 counter on it for each land you had enter the battlefield under your control this turn.

Rise of the Dark Realms

Put all creature cards from all graveyards onto the battlefield under your control.

Orzhov Signet

Nissa's Expedition

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Drowned Catacomb

Drowned Catacomb enters tapped unless you control an Island or a Swamp.
{T}: Add {U} or {B}.

Nature's Lore

Search your library for a Forest card, put that card onto the battlefield, then shuffle.

Urza, Lord Protector

Artifact, instant, and sorcery spells you cast cost {1} less to cast.
{7}: If you both own and control Urza, Lord Protector and an artifact named The Mightstone and Weakstone, exile them, then meld them into Urza, Planeswalker. Activate only as a sorcery.

Farseek

Search your library for a Plains, Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

Haughty Djinn

Flying
Haughty Djinn's power is equal to the number of instant and sorcery cards in your graveyard.
Instant and sorcery spells you cast cost {1} less to cast.

Fated Return

Put target creature card from a graveyard onto the battlefield under your control. It gains indestructible. If it's your turn, scry 2.

Vadrik, Astral Archmage

If it's neither day nor night, it becomes day as Vadrik, Astral Archmage enters.
Instant and sorcery spells you cast cost {X} less to cast, where X is Vadrik's power.
Whenever day becomes night or night becomes day, put a +1/+1 counter on Vadrik.

Growth Spiral

Draw a card. You may put a land card from your hand onto the battlefield.

Quantum Misalignment

Create a token that's a copy of target creature you control, except it isn't legendary.
Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)

Elminster's Simulacrum

For each opponent, you create a token that's a copy of up to one target creature that player controls.

Forest

Too Greedily, Too Deep

Put target creature card from a graveyard onto the battlefield under your control. That creature deals damage equal to its power to each other creature.

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Case of the Ransacked Lab

Instant and sorcery spells you cast cost {1} less to cast.
To solve — You've cast four or more instant and sorcery spells this turn. (If unsolved, solve at the beginning of your end step.)
Solved — Whenever you cast an instant or sorcery spell, draw a card.

Thrilling Encore

Put onto the battlefield under your control all creature cards in all graveyards that were put there from the battlefield this turn.

Clifftop Retreat

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

Dimir Signet

Broken Bond

Destroy target artifact or enchantment. You may put a land card from your hand onto the battlefield.

Path of the Schemer

Each player mills two cards. Then you put a creature card from a graveyard onto the battlefield under your control. It's an artifact in addition to its other types.
Will of the Planeswalkers — Starting with you, each player votes for planeswalk or chaos. If planeswalk gets more votes, planeswalk. If chaos gets more votes or the vote is tied, chaos ensues.

Myriad Landscape

Myriad Landscape enters tapped.
{T}: Add {C}.
{2}, {T}, Sacrifice Myriad Landscape: Search your library for up to two basic land cards that share a land type, put them onto the battlefield tapped, then shuffle.

Rootbound Crag

Rootbound Crag enters tapped unless you control a Mountain or a Forest.
{T}: Add {R} or {G}.

Wayfarer's Bauble

{2}, {T}, Sacrifice Wayfarer's Bauble: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Atarka's Command

Choose two —
• Your opponents can't gain life this turn.
• Atarka's Command deals 3 damage to each opponent.
• You may put a land card from your hand onto the battlefield.
• Creatures you control get +1/+1 and gain reach until end of turn.

Prairie Stream

({T}: Add {W} or {U}.)
Prairie Stream enters tapped unless you control two or more basic lands.

Izzet Signet

Sunken Hollow

({T}: Add {U} or {B}.)
Sunken Hollow enters tapped unless you control two or more basic lands.

Joint Exploration

Kicker {G} (You may pay an additional {G} as you cast this spell.)
Scry 2, then draw a card. If this spell was kicked, you may put a land card from your hand onto the battlefield.

Treacherous Urge

Target opponent reveals their hand. You may put a creature card from it onto the battlefield under your control. That creature gains haste. Sacrifice it at the beginning of the next end step.

Swamp

Boros Signet

Sunpetal Grove

Sunpetal Grove enters tapped unless you control a Forest or a Plains.
{T}: Add {G} or {W}.

Baral, Chief of Compliance

Instant and sorcery spells you cast cost {1} less to cast.
Whenever a spell or ability you control counters a spell, you may draw a card. If you do, discard a card.

Isolated Chapel

Isolated Chapel enters tapped unless you control a Plains or a Swamp.
{T}: Add {W} or {B}.

Hinterland Harbor

Hinterland Harbor enters tapped unless you control a Forest or an Island.
{T}: Add {G} or {U}.

Plains

Reanimate

Put target creature card from a graveyard onto the battlefield under your control. You lose life equal to its mana value.

Woodland Cemetery

Woodland Cemetery enters tapped unless you control a Swamp or a Forest.
{T}: Add {B} or {G}.

Simic Signet

Boneyard Parley

Exile up to five target creature cards from graveyards. An opponent separates those cards into two piles. Put all cards from the pile of your choice onto the battlefield under your control and the rest into their owners' graveyards.

Irenicus's Vile Duplication

Create a token that's a copy of target creature you control, except the token has flying and it isn't legendary.

Goblin Electromancer

Instant and sorcery spells you cast cost {1} less to cast.

Vat Emergence

Put target creature card from a graveyard onto the battlefield under your control. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Yawgmoth's Vile Offering

(You may cast a legendary sorcery only if you control a legendary creature or planeswalker.)
Put up to one target creature or planeswalker card from a graveyard onto the battlefield under your control. Destroy up to one target creature or planeswalker. Exile Yawgmoth's Vile Offering.

Cinder Glade

({T}: Add {R} or {G}.)
Cinder Glade enters tapped unless you control two or more basic lands.

Sol Ring

Island

Endless Obedience

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Put target creature card from a graveyard onto the battlefield under your control.

Worldsoul's Rage

Worldsoul's Rage deals X damage to any target. Put up to X land cards from your hand and/or graveyard onto the battlefield tapped.

Temple of the False God

{T}: Add {C}{C}. Activate only if you control five or more lands.

Mountain

Ghastly Conscription

Exile all creature cards from target player's graveyard in a face-down pile, shuffle that pile, then manifest those cards. (To manifest a card, put it onto the battlefield face down as a 2/2 creature. Turn it face up any time for its mana cost if it's a creature card.)

Three Visits

Search your library for a Forest card, put it onto the battlefield, then shuffle.

Rise from the Grave

Put target creature card from a graveyard onto the battlefield under your control. That creature is a black Zombie in addition to its other colors and types.

Breach the Multiverse

Each player mills ten cards. For each player, choose a creature or planeswalker card in that player's graveyard. Put those cards onto the battlefield under your control. Then each creature you control becomes a Phyrexian in addition to its other types.