Dragonlair Spider

Reach
Whenever an opponent casts a spell, create a 1/1 green Insect creature token.

Forest

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.)

Nyx Weaver

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

Mountain

Prevent all combat damage that would be dealt this turn.

Mirkwood Spider

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

Sporecap Spider

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.

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.

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.

Archetype of Finality

Creatures you control have deathtouch.
Creatures your opponents control lose deathtouch and can't have or gain deathtouch.

Twin-Silk Spider

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

Terrifying Presence

Prevent all combat damage that would be dealt by creatures other than target creature this turn.

Steam Spitter

Reach (This creature can block creatures with flying.)
{R}: Steam Spitter gets +1/+0 until end of turn.

Obscuring Haze

If you control a commander, you may cast this spell without paying its mana cost.
Prevent all damage that would be dealt this turn by creatures your opponents control.

Lolth, Spider Queen

Whenever a creature you control dies, put a loyalty counter on Lolth, Spider Queen.
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."

Silklash Spider

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

Drider

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

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.

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.

Penumbra Spider

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

Ancient Lumberknot

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

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.

Watcher in the Web

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

Ruins Recluse

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

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.

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.

Giant Trap Door Spider

{1}{R}{G}, {T}: Exile Giant Trap Door Spider and target creature without flying that's attacking you.

Swamp

Thantis, the Warweaver

Vigilance, reach
All creatures attack each combat if able.
Whenever a creature attacks you or a planeswalker you control, put a +1/+1 counter on Thantis, the Warweaver.

Brood Weaver

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

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.

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."

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.

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.)

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.