Path of Discovery

Whenever a creature you control enters, it explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on the creature, then put the card back or put it into your graveyard.)

Elesh Norn, Grand Cenobite

Vigilance
Other creatures you control get +2/+2.
Creatures your opponents control get -2/-2.

Aura Shards

Whenever a creature you control enters, you may destroy target artifact or enchantment.

Soul of the Harvest

Trample
Whenever another nontoken creature you control enters, you may draw a card.

Aid from the Cowl

Revolt — At the beginning of your end step, if a permanent you controlled left the battlefield this turn, reveal the top card of your library. If it's a permanent card, you may put it onto the battlefield. Otherwise, you may put it on the bottom of your library.

Arcane Signet

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

Reclamation Sage

When Reclamation Sage enters, you may destroy target artifact or enchantment.

Heronblade Elite

Vigilance
Whenever another Human you control enters, put a +1/+1 counter on Heronblade Elite.
{T}: Add X mana of any one color, where X is Heronblade Elite's power.

Abrade

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

Pandemonium

Whenever a creature enters, that creature's controller may have it deal damage equal to its power to any target of their choice.

Plains

Blessed Sanctuary

Prevent all noncombat damage that would be dealt to you and creatures you control.
Whenever a nontoken creature you control enters, create a 2/2 white Unicorn creature token.

Relic of Legends

{T}: Add one mana of any color.
Tap an untapped legendary creature you control: Add one mana of any color.

Sterling Grove

Other enchantments you control have shroud. (They can't be the targets of spells or abilities.)
{1}, Sacrifice Sterling Grove: Search your library for an enchantment card, reveal it, then shuffle and put that card on top.

Boros Cluestone

{T}: Add {R} or {W}.
{R}{W}, {T}, Sacrifice Boros Cluestone: Draw a card.

Cultivate

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Rumor Gatherer

Alliance — Whenever another creature you control enters, scry 1. If this is the second time this ability has resolved this turn, draw a card instead.

Rocco, Cabaretti Caterer

When Rocco, Cabaretti Caterer enters, if you cast it, you may search your library for a creature card with mana value X or less, put it onto the battlefield, then shuffle.

Norin the Wary

When a player casts a spell or a creature attacks, exile Norin the Wary. Return it to the battlefield under its owner's control at the beginning of the next end step.

Path of Ancestry

Path of Ancestry 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.)

Soul Warden

Whenever another creature enters, you gain 1 life.

Swords to Plowshares

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

Mountain

Windborn Muse

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

Yoshimaru, Ever Faithful

Whenever another legendary permanent you control enters, put a +1/+1 counter on Yoshimaru, Ever Faithful.
Partner (You can have two commanders if both have partner.)

Eidolon of Blossoms

Constellation — Whenever Eidolon of Blossoms or another enchantment you control enters, draw a card.

Champion of Lambholt

Creatures with power less than Champion of Lambholt's power can't block creatures you control.
Whenever another creature you control enters, put a +1/+1 counter on Champion of Lambholt.

Gala Greeters

Alliance — Whenever another creature you control enters, choose one that hasn't been chosen this turn —
• Put a +1/+1 counter on Gala Greeters.
• Create a tapped Treasure token.
• You gain 2 life.

Sphere of Safety

Creatures can't attack you or planeswalkers you control unless their controller pays {X} for each of those creatures, where X is the number of enchantments you control.

Venerated Rotpriest

Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)
Whenever a creature you control becomes the target of a spell, target opponent gets a poison counter.

Abiding Grace

At the beginning of your end step, choose one —
• You gain 1 life.
• Return target creature card with mana value 1 from your graveyard to the battlefield.

Teyo, the Shieldmage

You have hexproof. (You can't be the target of spells or abilities your opponents control.)
−2: Create a 0/3 white Wall creature token with defender.

Genesis Chamber

Whenever a nontoken creature enters, if Genesis Chamber is untapped, that creature's controller creates a 1/1 colorless Myr artifact creature token.

Wrath of God

Destroy all creatures. They can't be regenerated.

Michiko Konda, Truth Seeker

Whenever a source an opponent controls deals damage to you, that player sacrifices a permanent.

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.

Forest

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Jungle Shrine

Jungle Shrine enters tapped.
{T}: Add {R}, {G}, or {W}.

Essence Warden

Swiftfoot Boots

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

Spirit Bonds

Whenever a nontoken creature you control enters, you may pay {W}. If you do, create a 1/1 white Spirit creature token with flying.
{1}{W}, Sacrifice a Spirit: Target non-Spirit creature gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Witty Roastmaster

Alliance — Whenever another creature you control enters, Witty Roastmaster deals 1 damage to each opponent.

Sun Titan

Vigilance
Whenever Sun Titan enters or attacks, you may return target permanent card with mana value 3 or less from your graveyard to the battlefield.

Panharmonicon

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

Kodama's Reach

Beast Within

Destroy target permanent. Its controller creates a 3/3 green Beast creature token.

Cabaretti Courtyard

When Cabaretti Courtyard 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.

Selesnya Locket

{T}: Add {G} or {W}.
{G/W}{G/W}{G/W}{G/W}, {T}, Sacrifice Selesnya Locket: Draw two cards.

Command Tower

Temur Sabertooth

{1}{G}: You may return another creature you control to its owner's hand. If you do, Temur Sabertooth gains indestructible until end of turn.

Ghostly Prison

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

Saltskitter

Whenever another creature enters, exile Saltskitter. Return Saltskitter to the battlefield under its owner's control at the beginning of the next end step.

Rampant Growth

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

Sol Ring

Boss's Chauffeur

Boss's Chauffeur enters with a number of +1/+1 counters on it equal to one plus the number of other creatures you control.
Alliance — Whenever another creature you control enters, put a +1/+1 counter on Boss's Chauffeur.
When Boss's Chauffeur dies, create a 1/1 green and white Citizen creature token for each +1/+1 counter on it.

Prosperous Innkeeper

When Prosperous Innkeeper enters, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
Whenever another creature you control enters, you gain 1 life.

Mortal's Resolve

Target creature gets +1/+1 and gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Impact Tremors

Whenever a creature you control enters, Impact Tremors deals 1 damage to each opponent.

Hero of Bretagard

Whenever one or more cards are put into exile from your hand or a spell or ability you control exiles one or more permanents from the battlefield, put that many +1/+1 counters on Hero of Bretagard.
As long as Hero of Bretagard has five or more counters on it, it has flying and is an Angel in addition to its other types.
As long as Hero of Bretagard has ten or more counters on it, it has indestructible and is a God in addition to its other types.

Rose Room Treasurer

Alliance — Whenever another creature you control enters, create a Treasure token if this is the first or second time this ability has resolved this turn. Otherwise, you may pay {X}. When you do, Rose Room Treasurer deals X damage to any target.

Gruul Locket

{T}: Add {R} or {G}.
{R/G}{R/G}{R/G}{R/G}, {T}, Sacrifice Gruul Locket: Draw two cards.

Warstorm Surge

Whenever a creature you control enters, it deals damage equal to its power to any target.

Farseek

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

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.

Prevent all combat damage that would be dealt this turn.

Exotic Orchard

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

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.

Squee, the Immortal

You may cast Squee, the Immortal from your graveyard or from exile.

Privileged Position

({G/W} can be paid with either {G} or {W}.)
Other permanents you control have hexproof. (They can't be the targets of spells or abilities your opponents control.)

Wirewood Symbiote

Return an Elf you control to its owner's hand: Untap target creature. Activate only once each turn.

Mentor of the Meek

Whenever another creature you control with power 2 or less enters, you may pay {1}. If you do, draw a card.

Destiny Spinner

Creature and enchantment spells you control can't be countered.
{3}{G}: Target land you control becomes an X/X Elemental creature with trample and haste until end of turn, where X is the number of enchantments you control. It's still a land.