Panharmonicon

If an artifact or creature entering causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Ledger Shredder

Flying
Whenever a player casts their second spell each turn, this creature connives. (Draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on this creature.)

Bitterbloom Bearer

Flash
Flying
At the beginning of your upkeep, you lose 1 life and create a 1/1 blue and black Faerie creature token with flying.

Auton Soldier

You may have this creature enter as a copy of any creature on the battlefield, except it isn't legendary, is an artifact in addition to its other types, and has myriad. (Whenever it 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.)

Ghostly Flicker

Exile two target artifacts, creatures, and/or lands you control, then return those cards to the battlefield under your control.

Tomb of Horrors Adventurer

When this creature enters, you take the initiative.
Whenever you cast your second spell each turn, copy it. If you've completed a dungeon, copy that spell twice instead. You may choose new targets for the copies. (A copy of a permanent spell becomes a token.)

Go for the Throat

Faerie Mastermind

Flash
Flying
Whenever an opponent draws their second card each turn, you draw a card.
{3}{U}: Each player draws a card.

Dungeon Delver

Commander creatures you own have "Room abilities of dungeons you own trigger an additional time."

Vorpal Sword

Equipped creature gets +2/+0 and has deathtouch.
{5}{B}{B}{B}: Until end of turn, this Equipment gains "Whenever equipped creature deals combat damage to a player, that player loses the game."
Equip {B}{B}

Safana, Calimport Cutthroat

Menace
At the beginning of your end step, if you have the initiative, create a Treasure token. Create three of those tokens instead if you've completed a dungeon.
Choose a Background (You can have a Background as a second commander.)

Rilsa Rael, Kingpin

Deathtouch
When Rilsa Rael enters, you take the initiative.
Whenever you attack, target attacking creature gains deathtouch until end of turn. If you've completed a dungeon, that creature also gets +5/+0 and gains first strike and menace until end of turn.

Vantress Visions

Copy target activated or triggered ability you control. You may choose new targets for the copy.

Virtue of Knowledge

If a permanent entering causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Virtue of Knowledge // Vantress Visions

Sarevok's Tome

When this artifact enters, you take the initiative.
{T}: Add {C}. If you have the initiative, add {C}{C} instead.
{3}, {T}: Exile cards from the top of your library until you exile a nonland card. You may cast that card without paying its mana cost. Activate only if you've completed a dungeon.

From the Catacombs

Put target creature card from a graveyard onto the battlefield under your control with a corpse counter on it. You take the initiative. If that creature would leave the battlefield, exile it instead of putting it anywhere else.
Escape—{3}{B}{B}, Exile five other cards from your graveyard. (You may cast this card from your graveyard for its escape cost.)

Halo Forager

Flying
When this creature enters, you may pay {X}. When you do, you may cast target instant or sorcery card with mana value X from a graveyard without paying its mana cost. If that spell would be put into a graveyard, exile it instead.

Essence Flux

Exile target creature you control, then return that card to the battlefield under its owner's control. If it's a Spirit, put a +1/+1 counter on it.

Imoen, Mystic Trickster

Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
At the beginning of your end step, if you have the initiative, draw a card. Draw another card if you've completed a dungeon.
Choose a Background (You can have a Background as a second commander.)

Ravenloft Adventurer

When this creature enters, you take the initiative.
If a creature an opponent controls would die, instead exile it and put a hit counter on it.
Whenever this creature attacks, if you've completed a dungeon, defending player loses 1 life for each card they own in exile with a hit counter on it.

Arcane Signet

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

Ornithopter of Paradise

Trailblazer's Torch

When this Equipment enters, you take the initiative.
Whenever equipped creature becomes blocked, it deals 2 damage to each creature blocking it.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Strixhaven Stadium

{T}: Add {C}. Put a point counter on this artifact.
Whenever a creature deals combat damage to you, remove a point counter from this artifact.
Whenever a creature you control deals combat damage to an opponent, put a point counter on this artifact. Then if it has ten or more point counters on it, remove them all and that player loses the game.

Grim Hireling

Whenever one or more creatures you control deal combat damage to a player, create two Treasure tokens.
{B}, Sacrifice X Treasures: Target creature gets -X/-X until end of turn. Activate only as a sorcery.

Propaganda

Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

Likeness Looter

Flying
{T}: Draw a card, then discard a card.
{X}: This creature becomes a copy of target creature card in your graveyard with mana value X, except it has flying and this ability. Activate only as a sorcery.

Baleful Strix

Flying, deathtouch
When this creature enters, draw a card.

Feywild Caretaker

When this creature enters, you take the initiative.
At the beginning of your end step, if you have the initiative, create a 1/1 blue Faerie Dragon creature token with flying.

Underdark Explorer

Menace (This creature can't be blocked except by two or more creatures.)
When this creature enters, you take the initiative.

Faerie Seer

Flying
When this creature enters, scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Reality Shift

Exile target creature. Its controller manifests the top card of their library. (That player puts the top card of their library onto the battlefield face down as a 2/2 creature. If it's a creature card, it can be turned face up any time for its mana cost.)

Paradox Haze

Enchant player
At the beginning of enchanted player's first upkeep each turn, that player gets an additional upkeep step after this step.

Invisible Stalker

Hexproof (This creature can't be the target of spells or abilities your opponents control.)
This creature can't be blocked.

Spark Double

You may have this creature enter as a copy of a creature or planeswalker you control, except it enters with an additional +1/+1 counter on it if it's a creature, it enters with an additional loyalty counter on it if it's a planeswalker, and it isn't legendary.

Vicious Battlerager

When this creature enters, you take the initiative.
Spiked Retribution — Whenever this creature becomes blocked by a creature, that creature's controller loses 5 life.

Passageway Seer

Lifelink
When this creature enters, you take the initiative.
At the beginning of your end step, if you have the initiative, put a +1/+1 counter on this creature.