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.

Colossification

Enchant creature
When Colossification enters, tap enchanted creature.
Enchanted creature gets +20/+20.

Kozilek, Butcher of Truth

When you cast this spell, draw four cards.
Annihilator 4 (Whenever this creature attacks, defending player sacrifices four permanents.)
When Kozilek, Butcher of Truth is put into a graveyard from anywhere, its owner shuffles their graveyard into their library.

Guildless Commons

Guildless Commons enters tapped.
When Guildless Commons enters, return a land you control to its owner's hand.
{T}: Add {C}{C}.

Helm of the Host

At the beginning of combat on your turn, create a token that's a copy of equipped creature, except the token isn't legendary. That token gains haste.
Equip {5}

Greensleeves, Maro-Sorcerer

Protection from planeswalkers and from Wizards
Greensleeves, Maro-Sorcerer's power and toughness are each equal to the number of lands you control.
Landfall — Whenever a land you control enters, create a 3/3 green Badger creature token.

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.

Dark Depths

Dark Depths enters with ten ice counters on it.
{3}: Remove an ice counter from Dark Depths.
When Dark Depths has no ice counters on it, sacrifice it. If you do, create Marit Lage, a legendary 20/20 black Avatar creature token with flying and indestructible.

Scute Swarm

Landfall — Whenever a land you control enters, create a 1/1 green Insect creature token. If you control six or more lands, create a token that's a copy of Scute Swarm instead.

Urza's Saga

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Urza's Saga gains "{T}: Add {C}."
II — Urza's Saga gains "{2}, {T}: Create a 0/0 colorless Construct artifact creature token with 'This creature gets +1/+1 for each artifact you control.'"
III — Search your library for an artifact card with mana cost {0} or {1}, put it onto the battlefield, then shuffle.

Zacama, Primal Calamity

Vigilance, reach, trample
When Zacama, Primal Calamity enters, if you cast it, untap all lands you control.
{2}{R}: Zacama deals 3 damage to target creature.
{2}{G}: Destroy target artifact or enchantment.
{2}{W}: You gain 3 life.

Exotic Orchard

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

Prosperous Partnership

When Prosperous Partnership enters, create two 1/1 green and white Citizen creature tokens.
Tap three untapped creatures you control: Create a Treasure token.

Sheltering Landscape

{T}: Add {C}.
{T}, Sacrifice Sheltering Landscape: Search your library for a basic Mountain, Forest, or Plains card, put it onto the battlefield tapped, then shuffle.
Cycling {R}{G}{W} ({R}{G}{W}, Discard this card: Draw a card.)

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.

Fortified Village

As Fortified Village enters, you may reveal a Forest or Plains card from your hand. If you don't, Fortified Village enters tapped.
{T}: Add {G} or {W}.

Sporemound

Landfall — Whenever a land you control enters, create a 1/1 green Saproling creature token.

Flawless Maneuver

If you control a commander, you may cast this spell without paying its mana cost.
Creatures you control gain indestructible until end of turn.

Talisman of Conviction

{T}: Add {C}.
{T}: Add {R} or {W}. Talisman of Conviction deals 1 damage to you.

Plains

Cinder Glade

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

Boros Charm

Choose one —
• Boros Charm deals 4 damage to target player or planeswalker.
• Permanents you control gain indestructible until end of turn.
• Target creature gains double strike until end of turn.

Naya Panorama

{T}: Add {C}.
{1}, {T}, Sacrifice Naya Panorama: Search your library for a basic Mountain, Forest, or Plains card, put it onto the battlefield tapped, then shuffle.

Jungle Shrine

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

Terramorphic Expanse

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

Game Trail

As Game Trail enters, you may reveal a Mountain or Forest card from your hand. If you don't, Game Trail enters tapped.
{T}: Add {R} or {G}.

Sarinth Greatwurm

Trample
Whenever a land enters, create a tapped Powerstone token. (It's an artifact with "{T}: Add {C}. This mana can't be spent to cast a nonartifact spell.")

Bruse Tarl, Boorish Herder

Whenever Bruse Tarl, Boorish Herder enters or attacks, target creature you control gains double strike and lifelink until end of turn.
Partner (You can have two commanders if both have partner.)

Evolving Wilds

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

Glorious Sunrise

At the beginning of combat on your turn, choose one —
• Creatures you control get +1/+1 and gain trample until end of turn.
• Target land gains "{T}: Add {G}{G}{G}" until end of turn.
• Draw a card if you control a creature with power 3 or greater.
• You gain 3 life.

Huatli, Radiant Champion

+1: Put a loyalty counter on Huatli, Radiant Champion for each creature you control.
−1: Target creature gets +X/+X until end of turn, where X is the number of creatures you control.
−8: You get an emblem with "Whenever a creature you control enters, you may draw a card."

Forest

Cathars' Crusade

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

Gruul Turf

Gruul Turf enters tapped.
When Gruul Turf enters, return a land you control to its owner's hand.
{T}: Add {R}{G}.

Selesnya Sanctuary

Selesnya Sanctuary enters tapped.
When Selesnya Sanctuary enters, return a land you control to its owner's hand.
{T}: Add {G}{W}.

Generous Gift

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

Ivy Lane Denizen

Whenever another green creature you control enters, put a +1/+1 counter on target creature.

Adventuring Gear

Landfall — Whenever a land you control enters, equipped creature gets +2/+2 until end of turn.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Sol Ring

Ajani's Welcome

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

Heroic Intervention

Permanents you control gain hexproof and indestructible until end of turn.

Ulamog, the Infinite Gyre

When you cast this spell, destroy target permanent.
Indestructible
Annihilator 4 (Whenever this creature attacks, defending player sacrifices four permanents.)
When Ulamog, the Infinite Gyre is put into a graveyard from anywhere, its owner shuffles their graveyard into their library.

Academy Manufactor

If you would create a Clue, Food, or Treasure token, instead create one of each.

The Great Henge

This spell costs {X} less to cast, where X is the greatest power among creatures you control.
{T}: Add {G}{G}. You gain 2 life.
Whenever a nontoken creature you control enters, put a +1/+1 counter on it and draw a card.

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.

Essence Warden

Whenever another creature enters, you gain 1 life.

Ashnod's Altar

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.

Talisman of Impulse

{T}: Add {C}.
{T}: Add {R} or {G}. Talisman of Impulse deals 1 damage to you.

Kodama's Reach

Teferi's Protection

Until your next turn, your life total can't change and you gain protection from everything. All permanents you control phase out. (While they're phased out, they're treated as though they don't exist. They phase in before you untap during your untap step.)
Exile Teferi's Protection.

Mayael's Aria

At the beginning of your upkeep, put a +1/+1 counter on each creature you control if you control a creature with power 5 or greater. Then you gain 10 life if you control a creature with power 10 or greater. Then you win the game if you control a creature with power 20 or greater.

Tireless Provisioner

Landfall — Whenever a land you control enters, create a Food token or a Treasure token. (Food is an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life." Treasure is an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Rampaging Baloths

Trample
Landfall — Whenever a land you control enters, you may create a 4/4 green Beast creature token.

Boros Garrison

Boros Garrison enters tapped.
When Boros Garrison enters, return a land you control to its owner's hand.
{T}: Add {R}{W}.

Retreat to Emeria

Landfall — Whenever a land you control enters, choose one —
• Create a 1/1 white Kor Ally creature token.
• Creatures you control get +1/+1 until end of turn.

Omnath, Locus of Rage

Landfall — Whenever a land you control enters, create a 5/5 red and green Elemental creature token.
Whenever Omnath, Locus of Rage or another Elemental you control dies, Omnath deals 3 damage to any target.

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.

Altar of Dementia

Sacrifice a creature: Target player mills cards equal to the sacrificed creature's power.

Aura Shards

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

Nylea, God of the Hunt

Indestructible
As long as your devotion to green is less than five, Nylea isn't a creature. (Each {G} in the mana costs of permanents you control counts toward your devotion to green.)
Other creatures you control have trample.
{3}{G}: Target creature gets +2/+2 until end of turn.

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.

Talisman of Unity

{T}: Add {C}.
{T}: Add {G} or {W}. Talisman of Unity deals 1 damage to you.

Warleader's Call

Creatures you control get +1/+1.
Whenever a creature you control enters, Warleader's Call deals 1 damage to each opponent.

Mountain

Unnatural Growth

At the beginning of each combat, double the power and toughness of each creature you control until end of turn.

Kodama of the East Tree

Reach
Whenever another permanent you control enters, if it wasn't put onto the battlefield with this ability, you may put a permanent card with equal or lesser mana value from your hand onto the battlefield.
Partner (You can have two commanders if both have partner.)

Scurry Oak

Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)
Whenever one or more +1/+1 counters are put on Scurry Oak, you may create a 1/1 green Squirrel creature token.

Jinnie Fay, Jetmir's Second

If you would create one or more tokens, you may instead create that many 2/2 green Cat creature tokens with haste or that many 3/1 green Dog creature tokens with vigilance.

Attended Socialite

Alliance — Whenever another creature you control enters, Attended Socialite gets +1/+1 until end of turn.

Canopy Vista

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

Impact Tremors

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

Command Tower

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

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.

Felidar Retreat

Landfall — Whenever a land you control enters, choose one —
• Create a 2/2 white Cat Beast creature token.
• Put a +1/+1 counter on each creature you control. Those creatures gain vigilance until end of turn.

Furycalm Snarl

As Furycalm Snarl enters, you may reveal a Mountain or Plains card from your hand. If you don't, Furycalm Snarl enters tapped.
{T}: Add {R} or {W}.

Warstorm Surge

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

Field of the Dead

Field of the Dead enters tapped.
{T}: Add {C}.
Whenever Field of the Dead or another land you control enters, if you control seven or more lands with different names, create a 2/2 black Zombie creature token.

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.

Arcane Signet

Beast Within

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