Aquastrand Spider

Graft 2 (This creature enters with two +1/+1 counters on it. Whenever another creature enters, you may move a +1/+1 counter from this creature onto it.)
{G}: Target creature with a +1/+1 counter on it gains reach until end of turn. (It can block creatures with flying.)

Have

Copper Longlegs

Reach
{1}{G}, Sacrifice Copper Longlegs: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

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.

Netcaster Spider

Reach (This creature can block creatures with flying.)
Whenever Netcaster Spider blocks a creature with flying, Netcaster Spider gets +2/+0 until end of turn.

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.

Ember Weaver

Reach (This creature can block creatures with flying.)
As long as you control a red permanent, Ember Weaver gets +1/+0 and has first strike.

Getting

Canopy Spider

Reach (This creature can block creatures with flying.)

Web Shot

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

Ettercap

Ettercap // Web Shot

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.

Drider

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

Arachnoid

Giant Spider

Jungle Weaver

Reach (This creature can block creatures with flying.)
Cycling {2} ({2}, Discard this card: Draw a card.)

Giant Trap Door Spider

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

Rib Cage Spider

Ancient Spider

First strike; reach (This creature can block creatures with flying.)

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.

Woolly Spider

Reach (This creature can block creatures with flying.)
Whenever Woolly Spider blocks a creature with flying, Woolly Spider gets +0/+2 until end of turn.

Hitchclaw Recluse

Silklash Spider

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

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.

Blightwidow

Reach (This creature can block creatures with flying.)
Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

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.

Steam Spitter

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

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.

Tangle Spider

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

Root Spider

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

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."

Sporecap Spider

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.

Plated Spider

Acid Web Spider

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

Ruins Recluse

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

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.")

Needlepeak Spider

Canoptek Spyder

Flying
Fabricator Claw Array — Whenever another nontoken artifact creature or Vehicle you control enters, draw a card.

Llanowar Greenwidow

Reach, trample
Domain — {7}{G}: Return Llanowar Greenwidow from your graveyard to the battlefield tapped. It gains "If this permanent would leave the battlefield, exile it instead of putting it anywhere else." This ability costs {1} less to activate for each basic land type among lands you control.

Sentinel Spider

Pale Recluse

Reach (This creature can block creatures with flying.)
Forestcycling {2}, plainscycling {2} ({2}, Discard this card: Search your library for a Forest or Plains card, reveal it, put it into your hand, then shuffle.)

Watcher in the Web

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

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.)

Dragonlair Spider

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

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.

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.

Thran Spider

Reach
When Thran Spider enters, you and target opponent each create a tapped Powerstone token.
{7}: Look at the top four cards of your library. You may reveal an artifact card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Brood Weaver

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

Deadly Recluse

Somberwald Spider

Reach (This creature can block creatures with flying.)
Morbid — Somberwald Spider enters with two +1/+1 counters on it if a creature died this turn.

Spitting Spider

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

Glowstone Recluse

Mutate {3}{G} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Reach
Whenever this creature mutates, put two +1/+1 counters on it.

Vilespawn Spider

Reach
At the beginning of your upkeep, mill a card. (Put the top card of your library into your graveyard.)
{2}{G}{U}, {T}, Sacrifice Vilespawn Spider: Create a 1/1 green Insect creature token for each creature card in your graveyard. Activate only as a sorcery.

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.

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.

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.

Penumbra Spider

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

Skysnare Spider

Vigilance (Attacking doesn't cause this creature to tap.)
Reach (This creature can block creatures with flying.)

Swift Spinner

Willing Test Subject

Reach
Whenever you roll a 4 or higher on a die, put a +1/+1 counter on Willing Test Subject.
{6}: Roll a six-sided die.

Graverobber Spider

Reach
{3}{B}: Graverobber Spider gets +X/+X until end of turn, where X is the number of creature cards in your graveyard. Activate only once each turn.

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.

Twin-Silk Spider

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

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.

Gnottvold Recluse

Archweaver

Gloomwidow

Reach
Gloomwidow can block only creatures with flying.

Juvenile Gloomwidow

Reach (This creature can block creatures with flying.)
Wither (This deals damage to creatures in the form of -1/-1 counters.)

Snarespinner

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

Webspinner Cuff

Reach
Equipped creature gets +1/+4 and has reach.
Reconfigure {4} ({4}: Attach to target creature you control; or unattach from a creature. Reconfigure only as a sorcery. While attached, this isn't a creature.)

Goliath Spider

Mammoth Spider

Grappler Spider

Mirkwood Spider

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

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.

Stingerfling Spider

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

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.

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.