Grist, the Hunger Tide

As long as Grist, the Hunger Tide isn't on the battlefield, it's a 1/1 Insect creature in addition to its other types.
+1: Create a 1/1 black and green Insect creature token, then mill a card. If an Insect card was milled this way, put a loyalty counter on Grist and repeat this process.
−2: You may sacrifice a creature. When you do, destroy target creature or planeswalker.
−5: Each opponent loses life equal to the number of creature cards in your graveyard.

Obelisk Spider

Reach
Whenever Obelisk Spider deals combat damage to a creature, put a -1/-1 counter on that creature.
Whenever you put one or more -1/-1 counters on a creature, each opponent loses 1 life and you gain 1 life.

Command Tower

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

Silklash Spider

Reach
{X}{G}{G}: Silklash Spider deals X damage to each creature with flying.

Arachnogenesis

Create X 1/2 green Spider creature tokens with reach, where X is the number of creatures attacking you. Prevent all combat damage that would be dealt this turn by non-Spider creatures.

Chainweb Aracnir

Reach
When Chainweb Aracnir enters, it deals damage equal to its power to target creature with flying an opponent controls.
Escape—{3}{G}{G}, Exile four other cards from your graveyard. (You may cast this card from your graveyard for its escape cost.)
Chainweb Aracnir escapes with three +1/+1 counters on it.

Ash Barrens

{T}: Add {C}.
Basic landcycling {1} ({1}, Discard this card: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.)

Evolving Wilds

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

Carrion Grub

Carrion Grub gets +X/+0, where X is the greatest power among creature cards in your graveyard.
When Carrion Grub enters, mill four cards. (Put the top four cards of your library into your graveyard.)

Live or Die

Choose one —
• Return target creature card from your graveyard to the battlefield.
• Destroy target creature.

Widow's Walk

Whenever a creature you control attacks alone, it gets +1/+0 and gains deathtouch until end of turn.
(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

Derelict Attic

When you unlock this door, you draw two cards and you lose 2 life.
(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

Derelict Attic // Widow's Walk

Come Back Wrong

Destroy target creature. If a creature card is put into a graveyard this way, return it to the battlefield under your control. Sacrifice it at the beginning of your next end step.

Deluge of Doom

All creatures get -X/-X until end of turn, where X is the number of card types among cards in your graveyard.

Sign in Blood

Target player draws two cards and loses 2 life.

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

Drownyard Temple

{T}: Add {C}.
{3}: Return Drownyard Temple from your graveyard to the battlefield tapped.

Frostweb Spider

Reach (This creature can block creatures with flying.)
Whenever Frostweb Spider blocks a creature with flying, put a +1/+1 counter on Frostweb Spider at end of combat.

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.

Spitting Spider

Reach (This creature can block creatures with flying.)
Sacrifice a land: Spitting Spider deals 1 damage to each creature with flying.

Cactarantula

This spell costs {1} less to cast if you control a Desert.
Reach
Whenever Cactarantula becomes the target of a spell or ability an opponent controls, you may draw a card.

Oran-Rief Recluse

Kicker {2}{G} (You may pay an additional {2}{G} as you cast this spell.)
Reach (This creature can block creatures with flying.)
When Oran-Rief Recluse enters, if it was kicked, destroy target creature with flying.

Deadbridge Chant

When Deadbridge Chant enters, mill ten cards.
At the beginning of your upkeep, choose a card at random in your graveyard. If it's a creature card, put it onto the battlefield. Otherwise, put it into your hand.

Sweet-Gum Recluse

Flash
Cascade
Reach
When Sweet-Gum Recluse enters, put three +1/+1 counters on each of any number of target creatures that entered this turn.

Give In to Violence

Target creature gets +2/+2 and gains lifelink until end of turn.

Glint Weaver

Reach
When Glint Weaver enters, distribute three +1/+1 counters among one, two, or three target creatures, then you gain life equal to the greatest toughness among creatures you control.

Giant Adephage

Trample
Whenever Giant Adephage deals combat damage to a player, create a token that's a copy of Giant Adephage.

Basilisk Collar

Equipped creature has deathtouch and lifelink. (Any amount of damage it deals to a creature is enough to destroy it. Damage dealt by this creature also causes you to gain that much life.)
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Mirkwood Bats

Flying
Whenever you create or sacrifice a token, each opponent loses 1 life.

For the Common Good

Create X tokens that are copies of target token you control. Then tokens you control gain indestructible until your next turn. You gain 1 life for each token you control.

Coordinated Clobbering

Tap one or two target untapped creatures you control. They each deal damage equal to their power to target creature an opponent controls.

Root Spider

Whenever Root Spider blocks, it gets +1/+0 and gains first strike until end of turn.

Night's Whisper

Anthropede

Reach
When Anthropede enters, you may discard a card or pay {2}. When you do, destroy target Room.

Snarespinner

Reach
Whenever Snarespinner blocks a creature with flying, Snarespinner gets +2/+0 until end of turn.

Drider

Reach
Whenever Drider deals combat damage to a player, create a 2/1 black Spider creature token with menace and reach.

Hoarding Recluse

Reach, deathtouch
When Hoarding Recluse dies, put up to one other target card from a graveyard on the bottom of its owner's library.

Pincer Spider

Kicker {3} (You may pay an additional {3} as you cast this spell.)
Reach (This creature can block creatures with flying.)
If Pincer Spider was kicked, it enters with a +1/+1 counter on it.

Spineseeker Centipede

When Spineseeker Centipede enters, search your library for a basic land card, reveal it, put it into your hand, then shuffle.
Delirium — Spineseeker Centipede gets +1/+2 and has vigilance as long as there are four or more card types among cards in your graveyard.

Have

Enduring Tenacity

Whenever you gain life, target opponent loses that much life.
When Enduring Tenacity 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.)

Murder

Arachnus Spinner

Reach
Tap an untapped Spider you control: Search your graveyard and/or library for a card named Arachnus Web and put it onto the battlefield attached to target creature. If you search your library this way, shuffle.

Rotwidow Pack

Reach
{3}{B}{G}, Exile a creature card from your graveyard: Create a 1/2 green Spider creature token with reach, then each opponent loses 1 life for each Spider you control.

Braids, Arisen Nightmare

At the beginning of your end step, you may sacrifice an artifact, creature, enchantment, land, or planeswalker. If you do, each opponent may sacrifice a permanent of their choice that shares a card type with it. For each opponent who doesn't, that player loses 2 life and you draw a card.

Temple of Malady

This land enters tapped.
When this land enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{T}: Add {B} or {G}.

Twin-Silk Spider

Reach
When Twin-Silk Spider enters, create a 1/2 green Spider creature token with reach.

Decree of Pain

Destroy all creatures. They can't be regenerated. Draw a card for each creature destroyed this way.
Cycling {3}{B}{B} ({3}{B}{B}, Discard this card: Draw a card.)
When you cycle Decree of Pain, all creatures get -2/-2 until end of turn.

Tranquil Thicket

Tranquil Thicket enters tapped.
{T}: Add {G}.
Cycling {G} ({G}, Discard this card: Draw a card.)

Reliquary Tower

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

Deathreap Ritual

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

Penumbra Spider

Reach
When Penumbra Spider dies, create a 2/4 black Spider creature token with reach.

Crawling Sensation

At the beginning of your upkeep, you may mill two cards. (You may put the top two cards of your library into your graveyard.)
Whenever one or more land cards are put into your graveyard from anywhere for the first time each turn, create a 1/1 green Insect creature token.

Mineshaft Spider

Reach
When Mineshaft Spider enters, you may mill two cards. (You may put the top two cards of your library into your graveyard.)

Reanimate

Put target creature card from a graveyard onto the battlefield under your control. You lose life equal to its mana value.

Final Vengeance

As an additional cost to cast this spell, sacrifice a creature or enchantment.
Exile target creature.

Ishkanah, Grafwidow

Reach
Delirium — When Ishkanah, Grafwidow enters, if there are four or more card types among cards in your graveyard, create three 1/2 green Spider creature tokens with reach.
{6}{B}: Target opponent loses 1 life for each Spider you control.

Access Maze

Once during each of your turns, you may cast a spell from your hand by paying life equal to its mana value rather than paying its mana cost.
(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

Cramped Vents

When you unlock this door, this Room deals 6 damage to target creature an opponent controls. You gain life equal to the excess damage dealt this way.
(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

Cramped Vents // Access Maze

Flesh Burrower

Deathtouch
Whenever Flesh Burrower attacks, another target creature you control gains deathtouch until end of turn.

Awakening Hall

When you unlock this door, return all creature cards from your graveyard to the battlefield.
(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

Funeral Room

Whenever a creature you control dies, each opponent loses 1 life and you gain 1 life.
(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

Funeral Room // Awakening Hall

Shelob's Ambush

Target creature gets +1/+2 and gains deathtouch until end of turn. Create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")

Bojuka Bog

Bojuka Bog enters tapped.
When Bojuka Bog enters, exile target player's graveyard.
{T}: Add {B}.

Altanak, the Thrice-Called

Trample
Whenever Altanak, the Thrice-Called becomes the target of a spell or ability an opponent controls, draw a card.
{1}{G}, Discard Altanak, the Thrice-Called: Return target land card from your graveyard to the battlefield tapped.

Acid Web Spider

Reach
When Acid Web Spider enters, you may destroy target Equipment.

Shelob, Child of Ungoliant

Deathtouch, ward {2}
Other Spiders you control have deathtouch and ward {2}.
Whenever another creature dealt damage this turn by a Spider you controlled dies, create a token that's a copy of that creature, except it's a Food artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life," and it loses all other card types.

Twitching Doll

{T}: Add one mana of any color. Put a nest counter on Twitching Doll.
{T}, Sacrifice Twitching Doll: Create a 2/2 green Spider creature token with reach for each counter on Twitching Doll. Activate only as a sorcery.

Vault of Whispers

Gray Merchant of Asphodel

When Gray Merchant of Asphodel enters, each opponent loses X life, where X is your devotion to black. You gain life equal to the life lost this way. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)

Culling Ritual

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

Overwhelming Stampede

Until end of turn, creatures you control gain trample and get +X/+X, where X is the greatest power among creatures you control.

Necroblossom Snarl

As Necroblossom Snarl enters, you may reveal a Swamp or Forest card from your hand. If you don't, Necroblossom Snarl enters tapped.
{T}: Add {B} or {G}.

Commune with Evil

Look at the top four cards of your library. Put one of them into your hand and the rest into your graveyard. You gain 3 life.

Golgari Rot Farm

Golgari Rot Farm enters tapped.
When Golgari Rot Farm enters, return a land you control to its owner's hand.
{T}: Add {B}{G}.

Blood Pact

Nyx Weaver

Reach
At the beginning of your upkeep, mill two cards. (Put the top two cards of your library into your graveyard.)
{1}{B}{G}, Exile Nyx Weaver: Return target card from your graveyard to your hand.

Swamp

Myriad Landscape

Myriad Landscape enters tapped.
{T}: Add {C}.
{2}, {T}, Sacrifice Myriad Landscape: Search your library for up to two basic land cards that share a land type, put them onto the battlefield tapped, then shuffle.

Funnel-Web Recluse

Reach
Morbid — When Funnel-Web Recluse enters, if a creature died this turn, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Keys to the House

{1}, {T}, Sacrifice Keys to the House: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.
{3}, {T}, Sacrifice Keys to the House: Lock or unlock a door of target Room you control. Activate only as a sorcery.

Cadaver Lab

When you unlock this door, return target creature card from your graveyard to your hand.
(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

Defiled Crypt

Whenever one or more cards leave your graveyard, create a 2/2 black Horror enchantment creature token. This ability triggers only once each turn.
(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

Defiled Crypt // Cadaver Lab

Forest

Thriving Moor

Thriving Moor enters tapped. As it enters, choose a color other than black.
{T}: Add {B} or one mana of the chosen color.

Rampant Growth

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

Terramorphic Expanse

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

Fate Unraveler

Whenever an opponent draws a card, Fate Unraveler deals 1 damage to that player.

Ruins Recluse

Reach, deathtouch
{3}{G}: Put a +1/+1 counter on Ruins Recluse.

Restless Cottage

Restless Cottage enters tapped.
{T}: Add {B} or {G}.
{2}{B}{G}: Restless Cottage becomes a 4/4 black and green Horror creature until end of turn. It's still a land.
Whenever Restless Cottage attacks, create a Food token and exile up to one target card from a graveyard.

Rickety Gazebo

When you unlock this door, mill four cards, then return up to two permanent cards from among them to your hand.
(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

Greenhouse

Lands you control have "{T}: Add one mana of any color."
(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

Greenhouse // Rickety Gazebo

Brainstone

{2}, {T}, Sacrifice Brainstone: Draw three cards, then put two cards from your hand on top of your library in any order.

Tree of Tales

Binding the Old Gods

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Destroy target nonland permanent an opponent controls.
II — Search your library for a Forest card, put it onto the battlefield tapped, then shuffle.
III — Creatures you control gain deathtouch until end of turn.

Three Tree City

As Three Tree City enters, choose a creature type.
{T}: Add {C}.
{2}, {T}: Choose a color. Add an amount of mana of that color equal to the number of creatures you control of the chosen type.

Woodland Cemetery

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

Mirkwood Spider

Deathtouch
Whenever Mirkwood Spider attacks, target legendary creature you control gains deathtouch until end of turn.

Stingerfling Spider

Reach
When Stingerfling Spider enters, you may destroy target creature with flying.

Sadistic Shell Game

Starting with the next opponent in turn order, each player chooses a creature you don't control. Destroy the chosen creatures.

Web Shot

Destroy target creature with flying. (Then exile this card. You may cast the creature later from exile.)