Arvinox, the Mind Flail

Arvinox, the Mind Flail isn't a creature unless you control three or more permanents you don't own.
At the beginning of your end step, exile the bottom card of each opponent's library face down. For as long as those cards remain exiled, you may look at them, you may cast permanent spells from among them, and you may spend mana as though it were mana of any color to cast those spells.

Gloomshrieker

Menace (This creature can't be blocked except by two or more creatures.)
When Gloomshrieker enters, return target permanent card from your graveyard to your hand.
If Gloomshrieker would die, exile it instead.

Fabled Passage

{T}, Sacrifice Fabled Passage: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle. Then if you control four or more lands, untap that land.

Craterhoof Behemoth

Haste
When Craterhoof Behemoth enters, creatures you control gain trample and get +X/+X until end of turn, where X is the number of creatures you control.

Trickster's Elk

Bestow {1}{G} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached.)
Enchanted creature loses all abilities and is a green Elk creature with base power and toughness 3/3.

Kami of Bamboo Groves

When Kami of Bamboo Groves enters the battlefield, you may put a land card from your hand onto the battlefield tapped.
Channel — {2}{G}, Discard Kami of Bamboo Groves: Conjure two cards named Forest into your hand.

Reliquary Tower

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

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.

Whip of Erebos

Creatures you control have lifelink.
{2}{B}{B}, {T}: Return target creature card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step. If it would leave the battlefield, exile it instead of putting it anywhere else. Activate only as a sorcery.

Nylea, Keen-Eyed

Indestructible
As long as your devotion to green is less than five, Nylea isn't a creature.
Creature spells you cast cost {1} less to cast.
{2}{G}: Reveal the top card of your library. If it's a creature card, put it into your hand. Otherwise, you may put it into your graveyard.

Deathreap Ritual

Morbid — At the beginning of each end step, if a creature died this turn, you may draw a card.

Springheart Nantuko

Bestow {1}{G}
Enchanted creature gets +1/+1.
Landfall — Whenever a land you control enters, you may pay {1}{G} if Springheart Nantuko is attached to a creature you control. If you do, create a token that's a copy of that creature. If you didn't create a token this way, create a 1/1 green Insect creature token.

Birds of Paradise

Zulaport Cutthroat

Whenever Zulaport Cutthroat or another creature you control dies, each opponent loses 1 life and you gain 1 life.

Tainted Wood

{T}: Add {C}.
{T}: Add {B} or {G}. Activate only if you control a Swamp.

Terramorphic Expanse

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

Go for the Throat

Evolving Wilds

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

Courser of Kruphix

Play with the top card of your library revealed.
You may play lands from the top of your library.
Landfall — Whenever a land you control enters, you gain 1 life.

Grismold, the Dreadsower

Trample
At the beginning of your end step, each player creates a 1/1 green Plant creature token.
Whenever a creature token dies, put a +1/+1 counter on Grismold, the Dreadsower.

Erebos, Bleak-Hearted

Indestructible
As long as your devotion to black is less than five, Erebos isn't a creature.
Whenever another creature you control dies, you may pay 2 life. If you do, draw a card.
{1}{B}, Sacrifice another creature: Target creature gets -2/-1 until end of turn.

Grim Guardian

Constellation — Whenever Grim Guardian or another enchantment you control enters, each opponent loses 1 life.

Damnation

Destroy all creatures. They can't be regenerated.

Valgavoth's Lair

Hexproof
Valgavoth's Lair enters tapped. As it enters, choose a color.
{T}: Add one mana of the chosen color.

Command Tower

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

Appendage Amalgam

Flash
Whenever Appendage Amalgam attacks, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Beast Within

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

Lampad of Death's Vigil

{1}, Sacrifice a creature: Each opponent loses 1 life and you gain 1 life.

Viridescent Bog

Grave Pact

Whenever a creature you control dies, each other player sacrifices a creature.

Rampant Growth

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

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.

Dockside Chef

{1}{B}, Sacrifice an artifact or creature: Draw a card.

Insidious Roots

Creature tokens you control have "{T}: Add one mana of any color."
Whenever one or more creature cards leave your graveyard, create a 0/1 green Plant creature token, then put a +1/+1 counter on each Plant you control.

Arasta of the Endless Web

Reach
Whenever an opponent casts an instant or sorcery spell, create a 1/2 green Spider creature token with reach.

Moldervine Reclamation

Whenever a creature you control dies, you gain 1 life and draw a card.

Arcane Signet

Strangling Grasp

Enchant creature or planeswalker an opponent controls
At the beginning of your upkeep, enchanted permanent's controller sacrifices a nonland permanent, then that player loses 1 life.

Vengeful Strangler

Vengeful Strangler can't block.
When Vengeful Strangler dies, return it to the battlefield transformed under your control attached to target creature or planeswalker an opponent controls.

Vengeful Strangler // Strangling Grasp

Honest Rutstein

When Honest Rutstein enters, return target creature card from your graveyard to your hand.
Creature spells you cast cost {1} less to cast.

Abrupt Decay

This spell can't be countered.
Destroy target nonland permanent with mana value 3 or less.

Kodama's Reach

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.

Swamp

Blood Artist

Whenever Blood Artist or another creature dies, target player loses 1 life and you gain 1 life.

Vault of Whispers

Dryad Arbor

(Dryad Arbor isn't a spell, it's affected by summoning sickness, and it has "{T}: Add {G}.")

Maelstrom Pulse

Destroy target nonland permanent and all other permanents with the same name as that permanent.

Doomwake Giant

Constellation — Whenever Doomwake Giant or another enchantment you control enters, creatures your opponents control get -1/-1 until end of turn.

Nylea's Colossus

Constellation — Whenever Nylea's Colossus or another enchantment you control enters, double target creature's power and toughness until end of turn.

Temple of Malady

Temple of Malady enters tapped.
When Temple of Malady enters, scry 1.
{T}: Add {B} or {G}.

Overgrown Tomb

({T}: Add {B} or {G}.)
As Overgrown Tomb enters, you may pay 2 life. If you don't, it enters tapped.

Oakheart Dryads

Constellation — Whenever Oakheart Dryads or another enchantment you control enters, target creature gets +1/+1 until end of turn.

Woodland Cemetery

Woodland Cemetery enters tapped unless you control a Swamp or a Forest.
{T}: Add {B} or {G}.

Enduring Vitality

Vigilance
Creatures you control have "{T}: Add one mana of any color."
When Enduring Vitality dies, if it was a creature, return it to the battlefield under its owner's control. It's an enchantment. (It's not a creature.)

Rendmaw, Creaking Nest

Menace, reach
When Rendmaw, Creaking Nest enters and whenever you play a card with two or more card types, each player creates a tapped 2/2 black Bird creature token with flying. The tokens are goaded for the rest of the game. (They attack each combat if able and attack a player other than you if able.)

Solemn Simulacrum

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

Tree of Tales

Darkmoss Bridge

Darkmoss Bridge enters tapped.
Indestructible
{T}: Add {B} or {G}.

Exotic Orchard

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

Maskwood Nexus

Creatures you control are every creature type. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.
{3}, {T}: Create a 2/2 blue Shapeshifter creature token with changeling. (It is every creature type.)

Aphemia, the Cacophony

Flying
At the beginning of your end step, you may exile an enchantment card from your graveyard. If you do, create a 2/2 black Zombie creature token.

Massacre Wurm

When Massacre Wurm enters, creatures your opponents control get -2/-2 until end of turn.
Whenever a creature an opponent controls dies, that player loses 2 life.

Biotransference

Creatures you control are artifacts in addition to their other types. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.
Whenever you cast an artifact spell, you lose 1 life and create a 2/2 black Necron Warrior artifact creature token.

Power Depot

Power Depot enters tapped.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast artifact spells or activate abilities of artifacts.
Modular 1

Nighthowler

Bestow {2}{B}{B} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Nighthowler and enchanted creature each get +X/+X, where X is the number of creature cards in all graveyards.

Phyrexian Arena

At the beginning of your upkeep, you draw a card and you lose 1 life.

Farseek

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

Weaver of Harmony

Other enchantment creatures you control get +1/+1.
{G}, {T}: Copy target activated or triggered ability you control from an enchantment source. You may choose new targets for the copy. (Mana abilities can't be targeted.)

Ornithopter of Paradise

Culling Ritual

Destroy each nonland permanent with mana value 2 or less. Add {B} or {G} for each permanent destroyed this way.

Assassin's Trophy

Destroy target permanent an opponent controls. Its controller may search their library for a basic land card, put it onto the battlefield, then shuffle.

Baba Lysaga, Night Witch

{T}, Sacrifice up to three permanents: If there were three or more card types among the sacrificed permanents, each opponent loses 3 life, you gain 3 life, and you draw three cards.

Nyxborn Behemoth

This spell costs {X} less to cast, where X is the total mana value of noncreature enchantments you control.
Trample
{1}{G}, Sacrifice another enchantment: Nyxborn Behemoth gains indestructible until end of turn.

Forest

Sanctum Weaver

{T}: Add X mana of any one color, where X is the number of enchantments you control.

Treasure Vault

{T}: Add {C}.
{X}{X}, {T}, Sacrifice Treasure Vault: Create X Treasure tokens.

Golgari Signet

Nature's Lore

Search your library for a Forest card, put that card onto the battlefield, then shuffle.

Noxious Revival

({G/P} can be paid with either {G} or 2 life.)
Put target card from a graveyard on top of its owner's library.

Demon of Fate's Design

Flying, trample
Once during each of your turns, you may cast an enchantment spell by paying life equal to its mana value rather than paying its mana cost.
{2}{B}, Sacrifice another enchantment: Demon of Fate's Design gets +X/+0 until end of turn, where X is the sacrificed enchantment's mana value.

A-Nezumi Prowler

Ninjutsu {1}{B} ({1}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
When Nezumi Prowler enters, put a deathtouch counter and a lifelink counter on target creature you control.

Eidolon of Blossoms

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

Deathcap Glade

Deathcap Glade enters tapped unless you control two or more other lands.
{T}: Add {B} or {G}.