Urborg, Tomb of Yawgmoth

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

Kindred Summons

Choose a creature type. Reveal cards from the top of your library until you reveal X creature cards of the chosen type, where X is the number of creatures you control of that type. Put those cards onto the battlefield, then shuffle the rest of the revealed cards into your library.

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.)

Gyome, Master Chef

Trample
At the beginning of your end step, create a number of Food tokens equal to the number of nontoken creatures you had enter under your control this turn.
{1}, Sacrifice a Food: Target creature gains indestructible until end of turn. Tap it.

Bojuka Bog

This land enters tapped.
When this land enters, exile target player's graveyard.
{T}: Add {B}.

Beast Within

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

Sentinel Spider

Verdant Catacombs

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

Lolth, Spider Queen

Whenever a creature you control dies, put a loyalty counter on Lolth.
0: You draw a card and you lose 1 life.
−3: Create two 2/1 black Spider creature tokens with menace and reach.
−8: You get an emblem with "Whenever an opponent is dealt combat damage by one or more creatures you control, if that player lost less than 8 life this turn, they lose life equal to the difference."

Urza's Incubator

As this artifact enters, choose a creature type.
Creature spells of the chosen type cost {2} less to cast.

Kindred Dominance

Choose a creature type. Destroy all creatures that aren't of the chosen type.

Savvy Hunter

Whenever this creature attacks or blocks, create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this token: You gain 3 life.")
Sacrifice two Foods: Draw a card.

Second Harvest

For each token you control, create a token that's a copy of that permanent.

Kessig Recluse

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

Heroic Intervention

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

Canopy Spider

Reach (This creature can block creatures with flying.)

Setessan Tactics

Strive — This spell costs {G} more to cast for each target beyond the first.
Until end of turn, any number of target creatures each get +1/+1 and gain "{T}: This creature fights another target creature."

Cryptolith Rite

Creatures you control have "{T}: Add one mana of any color."

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.

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.

Night's Whisper

Takenuma, Abandoned Mire

{T}: Add {B}.
Channel — {3}{B}, Discard this card: Mill three cards, then return a creature or planeswalker card from your graveyard to your hand. This ability costs {1} less to activate for each legendary creature you control.

Door of Destinies

As this artifact enters, choose a creature type.
Whenever you cast a spell of the chosen type, put a charge counter on this artifact.
Creatures you control of the chosen type get +1/+1 for each charge counter on this artifact.

Talisman of Resilience

{T}: Add {C}.
{T}: Add {B} or {G}. This artifact deals 1 damage to you.

Viridescent Bog

Deadly Recluse

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.

Golgari Signet

Penumbra Spider

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

Blooming Marsh

This land enters tapped unless you control two or fewer other lands.
{T}: Add {B} or {G}.

Swamp

Metallic Mimic

As this creature enters, choose a creature type.
This creature is the chosen type in addition to its other types.
Each other creature you control of the chosen type enters with an additional +1/+1 counter on it.

Cosmic Hunger

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

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice this artifact: Draw a card.

Skyfisher Spider

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

Golgari Charm

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

Obelisk Spider

Reach
Whenever this creature 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.

Twilight Mire

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

Patriarch's Bidding

Each player chooses a creature type. Each player returns all creature cards of a type chosen this way from their graveyard to the battlefield.

Swift Spinner

Flash (You may cast this spell any time you could cast an instant.)
Reach (This creature can block creatures with flying.)

Tail Swipe

Choose target creature you control and target creature you don't control. If you cast this spell during your main phase, the creature you control gets +1/+1 until end of turn. Then those creatures fight each other. (Each deals damage equal to its power to the other.)

Gingerbread Cabin

({T}: Add {G}.)
This land enters tapped unless you control three or more other Forests.
When this land enters untapped, create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this token: You gain 3 life.")

Deathcap Glade

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

Realmwalker

Changeling (This card is every creature type.)
As this creature 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.

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.

Ulvenwald Tracker

{1}{G}, {T}: Target creature you control fights another target creature.

Ashnod's Altar

Arcane Signet

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

Jaheira, Friend of the Forest

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

Gilded Goose

Flying
When this creature enters, create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this token: You gain 3 life.")
{1}{G}, {T}: Create a Food token.
{T}, Sacrifice a Food: Add one mana of any color.

Overgrown Tomb

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

Nature's Lore

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

Beastmaster Ascension

Whenever a creature you control attacks, you may put a quest counter on this enchantment.
As long as this enchantment has seven or more quest counters on it, creatures you control get +5/+5.

Mirkwood Spider

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

Culling Ritual

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

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.

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."

Watcher in the Web

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

Command Tower

Silklash Spider

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

Undergrowth Stadium

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

Academy Manufactor

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

Frostweb Spider

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

Three Visits

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

Boxing Ring

Whenever a creature you control enters, it fights up to one target creature you don't control with the same mana value.
{T}: Create a Treasure token. Activate only if you control a creature that fought this turn.

Halana, Kessig Ranger

Reach
Whenever another creature you control enters, you may pay {2}. When you do, that creature deals damage equal to its power to target creature.
Partner (You can have two commanders if both have partner.)

Village Rites

As an additional cost to cast this spell, sacrifice a creature.
Draw two cards.

Woodland Cemetery

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

Boseiju, Who Endures

{T}: Add {G}.
Channel — {1}{G}, Discard this card: 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.

Drider

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

Ancient Lumberknot

Each creature you control with toughness greater than its power assigns combat damage equal to its toughness rather than its power.

Sakura-Tribe Elder

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

Twin-Silk Spider

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

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 token: You gain 3 life," and it loses all other card types.

Prevent all combat damage that would be dealt this turn.

Moldervine Reclamation

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

Forest

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.

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.

Sol Ring

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.

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.)