Sluiceway Scorpion

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
Scavenge {1}{B}{G} ({1}{B}{G}, Exile this card from your graveyard: Put a number of +1/+1 counters equal to this card's power on target creature. Scavenge only as a sorcery.)

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.

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.

Jungle Hollow

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {B} or {G}.

Brain Weevil

Intimidate (This creature can't be blocked except by artifact creatures and/or creatures that share a color with it.)
Sacrifice Brain Weevil: Target player discards two cards. Activate only as a sorcery.

Tangle Spider

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

Brain Maggot

When Brain Maggot enters, target opponent reveals their hand and you choose a nonland card from it. Exile that card until Brain Maggot leaves the battlefield.

Sentinel Spider

Moldgraf Millipede

When Moldgraf Millipede enters, mill three cards, then put a +1/+1 counter on Moldgraf Millipede for each creature card in your graveyard. (To mill three cards, put the top three cards of your library into your graveyard.)

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.

Crawling Infestation

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 creature cards are put into your graveyard from anywhere during your turn, create a 1/1 green Insect creature token. This ability triggers only once each turn.

Serrated Scorpion

When Serrated Scorpion dies, it deals 2 damage to each opponent and you gain 2 life.

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."

Sedge Scorpion

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

Wasteland Scorpion

Deathtouch
Cycling {2} ({2}, Discard this card: Draw a card.)

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.)

Blanchwood Armor

Enchant creature
Enchanted creature gets +1/+1 for each Forest you control.

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.

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.)

Consign to Dust

Strive — This spell costs {2}{G} more to cast for each target beyond the first.
Destroy any number of target artifacts and/or enchantments.

Rabid Bite

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

Carrion Locust

Flying
When Carrion Locust enters, exile target card from an opponent's graveyard. If it was a creature card, that player loses 1 life.

Spider Umbra

Enchant creature
Enchanted creature gets +1/+1 and has reach. (It can block creatures with flying.)
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Opulent Palace

Opulent Palace enters tapped.
{T}: Add {B}, {G}, or {U}.

Virus Beetle

When Virus Beetle enters, each opponent discards a card.

Snarespinner

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

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.

Toxic Scorpion

Deathtouch
When Toxic Scorpion enters, another target creature you control gains deathtouch until end of turn.

The World Spell

Read ahead (Choose a chapter and start with that many lore counters. Add one after your draw step. Skipped chapters don't trigger. Sacrifice after III.)
I, II — Look at the top seven cards of your library. You may reveal a non-Saga permanent card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.
III — Put up to two non-Saga permanent cards from your hand onto the battlefield.

Forest

Fell Stinger

Deathtouch
Exploit (When this creature enters, you may sacrifice a creature.)
When Fell Stinger exploits a creature, target player draws two cards and loses 2 life.

Swamp

Colossal Majesty

At the beginning of your upkeep, if you control a creature with power 4 or greater, draw a card.

Blister Beetle

When Blister Beetle enters, target creature gets -1/-1 until end of turn.

Haywire Mite

When Haywire Mite dies, you gain 2 life.
{G}, Sacrifice Haywire Mite: Exile target noncreature artifact or noncreature enchantment.

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.

Disfigure

Target creature gets -2/-2 until end of turn.

Chainflail Centipede

Whenever Chainflail Centipede or equipped creature attacks, it gets +2/+0 until end of turn.
Reconfigure {2} ({2}: Attach to target creature you control; or unattach from a creature. Reconfigure only as a sorcery. While attached, this isn't a creature.)

Hero's Downfall

Brood Weaver

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