Urborg, Tomb of Yawgmoth

Each land is a Swamp in addition to its other land types.

Curse of Clinging Webs

Enchant player
Whenever a nontoken creature enchanted player controls dies, exile it and you create a 1/2 green Spider creature token with reach.

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.

Legolas's Quick Reflexes

Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
Untap target creature. Until end of turn, it gains hexproof, reach, and "Whenever this creature becomes tapped, it deals damage equal to its power to up to one target creature."

Nature's Lore

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

Demonic Tutor

Search your library for a card, put that card into your hand, then shuffle.

Bite Down

Target creature you control deals damage equal to its power to target creature or planeswalker you don't control.

Arcane Signet

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

Golgari Charm

Choose one —
• All creatures get -1/-1 until end of turn.
• Destroy target enchantment.
• Regenerate each creature you control.

Jaheira, Friend of the Forest

Tokens you control have "{T}: Add {G}."
Choose a Background (You can have a Background as a second commander.)

Mirkwood Spider

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

Parallel Lives

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

Silklash Spider

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

Twilight Mire

{T}: Add {C}.
{B/G}, {T}: Add {B}{B}, {B}{G}, or {G}{G}.

Phyrexian Arena

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

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.

Realmwalker

Changeling (This card is every creature type.)
As Realmwalker enters, choose a creature type.
You may look at the top card of your library any time.
You may cast creature spells of the chosen type from the top of your library.

Stew the Coneys

Target creature you control deals damage equal to its power to target creature you don't control. Create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")

Forest

Roaming Throne

Ward {2}
As Roaming Throne enters, choose a creature type.
Roaming Throne is the chosen type in addition to its other types.
If a triggered ability of another creature you control of the chosen type triggers, it triggers an additional time.

Spider Food

Destroy up to one target artifact, enchantment, or creature with flying. Create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")

Undergrowth Stadium

Undergrowth Stadium enters tapped unless you have two or more opponents.
{T}: Add {B} or {G}.

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.

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.

Cabal Coffers

{2}, {T}: Add {B} for each Swamp you control.

Reliquary Tower

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

Last March of the Ents

This spell can't be countered.
Draw cards equal to the greatest toughness among creatures you control, then put any number of creature cards from your hand onto the battlefield.

Rampant Growth

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

Night of the Sweets' Revenge

When Night of the Sweets' Revenge enters, create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")
Foods you control have "{T}: Add {G}."
{5}{G}{G}, Sacrifice Night of the Sweets' Revenge: Creatures you control get +X/+X until end of turn, where X is the number of Foods you control. Activate only as a sorcery.

Thornbite Staff

Equipped creature has "{2}, {T}: This creature deals 1 damage to any target" and "Whenever a creature dies, untap this creature."
Whenever a Shaman creature enters, you may attach Thornbite Staff to it.
Equip {4}

Spider Spawning

Create a 1/2 green Spider creature token with reach for each creature card in your graveyard.
Flashback {6}{B} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

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.

Farseek

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

Cosmic Hunger

Target creature you control deals damage equal to its power to another target creature, planeswalker, or battle.

Tribute to the World Tree

Whenever a creature you control enters, draw a card if its power is 3 or greater. Otherwise, put two +1/+1 counters on it.

Sporeweb Weaver

Reach, hexproof from blue
Whenever Sporeweb Weaver is dealt damage, you gain 1 life and create a 1/1 green Saproling creature token.

Watcher in the Web

Reach (This creature can block creatures with flying.)
Watcher in the Web can block an additional seven creatures each combat.

Overgrown Tomb

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

Swamp

Tainted Wood

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

Sakura-Tribe Elder

Sacrifice Sakura-Tribe Elder: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Skyfisher Spider

Reach
When Skyfisher Spider enters, you may sacrifice another creature. When you do, destroy target nonland permanent.
When Skyfisher Spider dies, you may gain 1 life for each creature card in your graveyard. If you do, exile Skyfisher Spider from your graveyard.

Deadly Recluse

Reach (This creature can block creatures with flying.)
Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

Drider

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

Cultivate

Swiftfoot Boots

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

Return of the Wildspeaker

Choose one —
• Draw cards equal to the greatest power among non-Human creatures you control.
• Non-Human creatures you control get +3/+3 until end of turn.

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.

Sol Ring

Academy Manufactor

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

Verdant Catacombs

{T}, Pay 1 life, Sacrifice Verdant Catacombs: Search your library for a Swamp or Forest card, put it onto the battlefield, then shuffle.

Bushwhack

Choose one —
• Search your library for a basic land card, reveal it, put it into your hand, then shuffle.
• Target creature you control fights target creature you don't control. (Each deals damage equal to its power to the other.)

Command Tower

Fynn, the Fangbearer

Deathtouch
Whenever a creature you control with deathtouch deals combat damage to a player, that player gets two poison counters. (A player with ten or more poison counters loses the game.)

Twin-Silk Spider

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

Golgari Signet

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.

Talisman of Resilience

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

Masked Vandal

Changeling (This card is every creature type.)
When Masked Vandal enters, you may exile a creature card from your graveyard. If you do, exile target artifact or enchantment an opponent controls.

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.

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Beast Within

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

Prizefight

Target creature you control fights target creature you don't control. (Each deals damage equal to its power to the other.)
Create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Penumbra Spider

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

Three Visits

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

Hatchery Spider

Reach
Undergrowth — When you cast this spell, reveal the top X cards of your library, where X is the number of creature cards in your graveyard. You may put a green permanent card with mana value X or less from among them onto the battlefield. Put the rest on the bottom of your library in a random order.

Vanquisher's Banner

As Vanquisher's Banner enters, choose a creature type.
Creatures you control of the chosen type get +1/+1.
Whenever you cast a creature spell of the chosen type, draw a card.

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 artifact: You gain 3 life.")
Sacrifice three Foods: Draw a card.

Shelob, Dread Weaver

Whenever a nontoken creature an opponent controls dies, exile it.
{2}{B}, Put a creature card exiled with Shelob, Dread Weaver into its owner's graveyard: Put two +1/+1 counters on Shelob. Draw a card.
{X}{1}{B}: Put target creature card with mana value X exiled with Shelob onto the battlefield tapped under your control.

Viridian Longbow

Equipped creature has "{T}: This creature deals 1 damage to any target."
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery. This card enters unattached and stays on the battlefield if the creature leaves.)

Ruins Recluse

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

Doom Weaver

Reach
Soulbond (You may pair this creature with another unpaired creature when either enters. They remain paired for as long as you control both of them.)
As long as Doom Weaver is paired with another creature, each of those creatures has "When this creature dies, draw cards equal to its power."

Swarmyard

{T}: Add {C}.
{T}: Regenerate target Insect, Rat, Spider, or Squirrel. (The next time it would be destroyed this turn, instead tap it, remove it from combat, and heal all damage on it.)

Yavimaya, Cradle of Growth

Each land is a Forest in addition to its other land types.

Black Market Connections

At the beginning of your first main phase, choose one or more —
• Sell Contraband — Create a Treasure token. You lose 1 life.
• Buy Information — Draw a card. You lose 2 life.
• Hire a Mercenary — Create a 3/2 colorless Shapeshifter creature token with changeling. You lose 3 life. (It has every creature type.)

Herald's Horn

As Herald's Horn enters, choose a creature type.
Creature spells you cast of the chosen type cost {1} less to cast.
At the beginning of your upkeep, look at the top card of your library. If it's a creature card of the chosen type, you may reveal it and put it into your hand.

Brood Weaver

Reach
When Brood Weaver dies, create a 1/2 green Spider creature token with reach.

Exotic Orchard

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

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.

Putrefy

Destroy target artifact or creature. It can't be regenerated.

Lightning Greaves

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

The Shire

The Shire enters tapped unless you control a legendary creature.
{T}: Add {G}.
{1}{G}, {T}, Tap an untapped creature you control: Create a Food token.

Roar of Challenge

All creatures able to block target creature this turn do so.
Ferocious — That creature gains indestructible until end of turn if you control a creature with power 4 or greater.

Boseiju, Who Endures

{T}: Add {G}.
Channel — {1}{G}, Discard Boseiju, Who Endures: Destroy target artifact, enchantment, or nonbasic land an opponent controls. That player may search their library for a land card with a basic land type, put it onto the battlefield, then shuffle. This ability costs {1} less to activate for each legendary creature you control.

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.

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}.

Assault Formation

Each creature you control assigns combat damage equal to its toughness rather than its power.
{G}: Target creature with defender can attack this turn as though it didn't have defender.
{2}{G}: Creatures you control get +0/+1 until end of turn.