Ensnared by the Mara

Each opponent faces a villainous choice — They exile cards from the top of their library until they exile a nonland card, then you may cast that card without paying its mana cost, or that player exiles the top four cards of their library and Ensnared by the Mara deals damage equal to the total mana value of those exiled cards to that player.

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.)

Seize the Spotlight

Each opponent chooses fame or fortune. For each player who chose fame, gain control of a creature that player controls until end of turn. Untap those creatures and they gain haste until end of turn. For each player who chose fortune, you draw a card and create a Treasure token.

Traitorous Blood

Gain control of target creature until end of turn. Untap it. It gains trample and haste until end of turn.

Goldspan Dragon

Flying, haste
Whenever this creature attacks or becomes the target of a spell, create a Treasure token.
Treasures you control have "{T}, Sacrifice this artifact: Add two mana of any one color."

Terramorphic Expanse

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Count on Luck

At the beginning of your upkeep, exile the top card of your library. You may play that card this turn.

Dolmen Gate

Prevent all combat damage that would be dealt to attacking creatures you control.

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 token: Add one mana of any color.")

Valakut Stoneforge

Valakut Awakening

Put any number of cards from your hand on the bottom of your library, then draw that many cards plus one.

Valakut Awakening // Valakut Stoneforge

Solemn Simulacrum

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

Karlach, Fury of Avernus

Whenever you attack, if it's the first combat phase of the turn, untap all attacking creatures. They gain first strike until end of turn. After this phase, there is an additional combat phase.
Choose a Background (You can have a Background as a second commander.)

Thran Dynamo

Goldlust Triad

Flying
Myriad (Whenever this creature attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)
Whenever this creature deals combat damage to a player, create a Treasure token.

Utvara Hellkite

Flying
Whenever a Dragon you control attacks, create a 6/6 red Dragon creature token with flying.

Rose, Cutthroat Raider

First strike
Raid — At end of combat on your turn, if you attacked this turn, create a Junk token for each opponent you attacked. (It's an artifact with "{T}, Sacrifice this token: Exile the top card of your library. You may play that card this turn. Activate only as a sorcery.")
Whenever you sacrifice a Junk, add {R}.

Zenith Chronicler

Whenever a player casts their first multicolored spell each turn, each other player draws a card.

Gilded Lotus

Mountain

Decanter of Endless Water

You have no maximum hand size.
{T}: Add one mana of any color.

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.)

Veilstone Amulet

Whenever you cast a spell, creatures you control can't be the targets of spells or abilities your opponents control this turn.

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

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.)

Descent into Avernus

At the beginning of your upkeep, put two descent counters on this enchantment. Then each player creates X Treasure tokens and this enchantment deals X damage to each player, where X is the number of descent counters on this enchantment.

Redirect Lightning

As an additional cost to cast this spell, pay 5 life or pay {2}.
Change the target of target spell or ability with a single target.

Trailblazer's Boots

Equipped creature has nonbasic landwalk. (It can't be blocked as long as defending player controls a nonbasic land.)
Equip {2}

Blasphemous Act

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

Sol Ring

Big Score

As an additional cost to cast this spell, discard a card.
Draw two cards and create two Treasure tokens. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")

Arcane Signet

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

Disrupt Decorum

Goad all creatures you don't control. (Until your next turn, those creatures attack each combat if able and attack a player other than you if able.)

Abrade

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

Maestros Theater

When this land enters, sacrifice it. When you do, search your library for a basic Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle and you gain 1 life.

Prowler's Helm

Equipped creature can't be blocked except by Walls.
Equip {2}

Twinflame Tyrant

Flying
If a source you control would deal damage to an opponent or a permanent an opponent controls, it deals double that damage instead.

Laelia, the Blade Reforged

Haste
Whenever Laelia attacks, exile the top card of your library. You may play that card this turn.
Whenever one or more cards are put into exile from your library and/or your graveyard, put a +1/+1 counter on Laelia.

Bladegriff Prototype

Flying
Whenever this creature deals combat damage to a player, destroy target nonland permanent of that player's choice that one of your opponents controls.

Opera Love Song

Choose one —
• Exile the top two cards of your library. You may play those cards until your next end step.
• One or two target creatures each get +2/+0 until end of turn.

Aggravated Assault

{3}{R}{R}: Untap all creatures you control. After this main phase, there is an additional combat phase followed by an additional main phase. Activate only as a sorcery.

Possibility Storm

Whenever a player casts a spell from their hand, that player exiles it, then exiles cards from the top of their library until they exile a card that shares a card type with it. That player may cast that card without paying its mana cost. Then they put all cards exiled with this enchantment on the bottom of their library in a random order.

Cabaretti Courtyard

When this land enters, sacrifice it. When you do, search your library for a basic Mountain, Forest, or Plains card, put it onto the battlefield tapped, then shuffle and you gain 1 life.

Unexpected Windfall

Tannuk, Steadfast Second

Other creatures you control have haste.
Artifact cards and red creature cards in your hand have warp {2}{R}. (You may cast a card from your hand for its warp cost. Exile that permanent at the beginning of the next end step, then you may cast it from exile on a later turn.)

Etali, Primal Storm

Whenever Etali attacks, exile the top card of each player's library, then you may cast any number of spells from among those cards without paying their mana costs.

Cait Sith, Fortune Teller

Lucky Slots — At the beginning of combat on your turn, scry 1, then exile the top card of your library. You may play that card this turn. When you exile a card this way, target creature you control gets +X/+0 until end of turn, where X is that card's mana value.

Professional Face-Breaker

Menace
Whenever one or more creatures you control deal combat damage to a player, create a Treasure token.
Sacrifice a Treasure: Exile the top card of your library. You may play that card this turn.

Tavern Brawler

Commander creatures you own have "At the beginning of your upkeep, exile the top card of your library. This creature gets +X/+0 until end of turn, where X is that card's mana value. You may play that card this turn."

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control. It can attack and {T} no matter when it came under your control.)
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Gogo, Mysterious Mime

At the beginning of combat on your turn, you may have Gogo become a copy of another target creature you control until end of turn, except its name is Gogo, Mysterious Mime. If you do, Gogo and that creature each get +2/+0 and gain haste until end of turn and attack this turn if able.

Gauntlet of Power

As this artifact enters, choose a color.
Creatures of the chosen color get +1/+1.
Whenever a basic land is tapped for mana of the chosen color, its controller adds an additional one mana of that color.

The Reaver Cleaver

Equipped creature gets +1/+1 and has trample and "Whenever this creature deals combat damage to a player or planeswalker, create that many Treasure tokens."
Equip {3}

Light Up the Stage

Spectacle {R} (You may cast this spell for its spectacle cost rather than its mana cost if an opponent lost life this turn.)
Exile the top two cards of your library. Until the end of your next turn, you may play those cards.

Iron Myr

Geode Rager

First strike
Landfall — Whenever a land you control enters, goad each creature target player controls. (Until your next turn, those creatures attack each combat if able and attack a player other than you if able.)

Untimely Malfunction

Choose one —
• Destroy target artifact.
• Change the target of target spell or ability with a single target.
• One or two target creatures can't block this turn.

Riveteers Overlook

When this land enters, sacrifice it. When you do, search your library for a basic Swamp, Mountain, or Forest card, put it onto the battlefield tapped, then shuffle and you gain 1 life.

Moraug, Fury of Akoum

Each creature you control gets +1/+0 for each time it has attacked this turn.
Landfall — Whenever a land you control enters, if it's your main phase, there's an additional combat phase after this phase. At the beginning of that combat, untap all creatures you control.

War Room

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

Insurrection

Untap all creatures and gain control of them until end of turn. They gain haste until end of turn.

Balefire Dragon

Flying
Whenever this creature deals combat damage to a player, it deals that much damage to each creature that player controls.

Neheb, the Eternal

Afflict 3 (Whenever this creature becomes blocked, defending player loses 3 life.)
At the beginning of each of your postcombat main phases, add {R} for each 1 life your opponents have lost this turn.

Parapet Thrasher

Flying
Whenever one or more Dragons you control deal combat damage to an opponent, choose one that hasn't been chosen this turn —
• Destroy target artifact that opponent controls.
• This creature deals 4 damage to each other opponent.
• Exile the top card of your library. You may play it this turn.

The Fire Crystal

Red spells you cast cost {1} less to cast.
Creatures you control have haste.
{4}{R}{R}, {T}: Create a token that's a copy of target creature you control. Sacrifice it at the beginning of the next end step.

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.

Evolving Wilds

Thought Vessel

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

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.

Reliquary Tower

Act of Treason

Gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn. (It can attack and {T} this turn.)

Wild Magic Surge

Destroy target permanent an opponent controls. Its controller reveals cards from the top of their library until they reveal a permanent card that shares a card type with that permanent. They put that card onto the battlefield and the rest on the bottom of their library in a random order.

Scourge of the Throne

Flying
Dethrone (Whenever this creature attacks the player with the most life or tied for most life, put a +1/+1 counter on it.)
Whenever this creature attacks for the first time each turn, if it's attacking the player with the most life or tied for most life, untap all attacking creatures. After this phase, there is an additional combat phase.

Horn of Greed

Whenever a player plays a land, that player draws a card.

Involuntary Employment

Gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn. Create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")