Pandemonium

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

Rootbound Crag

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

Panharmonicon

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

Clifftop Retreat

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

Confusion in the Ranks

Whenever an artifact, creature, or enchantment enters, its controller chooses target permanent another player controls that shares a card type with it. Exchange control of those permanents.

Arcane Signet

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

Altar of the Brood

Whenever another permanent you control enters, each opponent mills 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.

Hinterland Sanctifier

Whenever another creature you control enters, you gain 1 life.

Hare Apparent

When this creature enters, create a number of 1/1 white Rabbit creature tokens equal to the number of other creatures you control named Hare Apparent.
A deck can have any number of cards named Hare Apparent.

Jungle Shrine

This land enters tapped.
{T}: Add {R}, {G}, or {W}.

Exotic Orchard

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

Angelic Chorus

Whenever a creature you control enters, you gain life equal to its toughness.

Impact Tremors

Whenever a creature you control enters, this enchantment deals 1 damage to each opponent.

Elspeth, Storm Slayer

If one or more tokens would be created under your control, twice that many of those tokens are created instead.
+1: Create a 1/1 white Soldier creature token.
0: Put a +1/+1 counter on each creature you control. Those creatures gain flying until your next turn.
−3: Destroy target creature an opponent controls with mana value 3 or greater.

Farseek

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

Mountain

Plains

Burst of Speed

Creatures you control gain haste until end of turn. (They can attack and {T} even if they just came under your control.)

Rabbit

Primal Vigor

If one or more tokens would be created, twice that many of those tokens are created instead.
If one or more +1/+1 counters would be put on a creature, twice that many +1/+1 counters are put on that creature instead.

Canopy Vista

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

Peregrin Took

If one or more tokens would be created under your control, those tokens plus an additional Food token are created instead. (It's an artifact with "{2}, {T}, Sacrifice this token: You gain 3 life.")
Sacrifice three Foods: Draw a card.

Thrumming Stone

Spells you cast have ripple 4. (Whenever you cast a spell, you may reveal the top four cards of your library. You may cast spells with the same name as that spell from among the revealed cards without paying their mana costs. Put the rest on the bottom of your library.)

Swords to Plowshares

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

Anointed Procession

If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead.

Temple of Civilization

(Transforms from Ojer Taq, Deepest Foundation.)
{T}: Add {W}.
{2}{W}, {T}: Transform this land. Activate only if you attacked with three or more creatures this turn and only as a sorcery.

Ojer Taq, Deepest Foundation

Vigilance
If one or more creature tokens would be created under your control, three times that many of those tokens are created instead.
When Ojer Taq dies, return it to the battlefield tapped and transformed under its owner's control.

Ojer Taq, Deepest Foundation // Temple of Civilization

Sunpetal Grove

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

Ajani's Welcome

Whenever a creature you control enters, you gain 1 life.

Doubling Season

If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead.
If an effect would put one or more counters on a permanent you control, it puts twice that many of those counters on that permanent instead.

Baylen, the Haymaker

Tap two untapped tokens you control: Add one mana of any color.
Tap three untapped tokens you control: Draw a card.
Tap four untapped tokens you control: Put three +1/+1 counters on Baylen. It gains trample until end of turn.

Mana Echoes

Whenever a creature enters, you may add an amount of {C} equal to the number of creatures you control that share a creature type with it.

Command Tower

Grand Crescendo

Create X 1/1 green and white Citizen creature tokens. Creatures you control gain indestructible until end of turn.

Forest

Cinder Glade

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

Parallel Lives

Aura Shards

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

Legion Loyalty

Creatures you control have myriad. (Whenever a creature with myriad 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.)

Mondrak, Glory Dominus

If one or more tokens would be created under your control, twice that many of those tokens are created instead.
{1}{W/P}{W/P}, Sacrifice two other artifacts and/or creatures: Put an indestructible counter on Mondrak. ({W/P} can be paid with either {W} or 2 life.)

Cathars' Crusade

Whenever a creature you control enters, put a +1/+1 counter on each creature you control.

Warleader's Call

Creatures you control get +1/+1.
Whenever a creature you control enters, this enchantment deals 1 damage to each opponent.

Path of Ancestry

This land 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.)