Mary Jane Watson

Whenever a Spider you control enters, draw a card. This ability triggers only once each turn.

Radioactive Spider

Reach, deathtouch
Fateful Bite — {2}, Sacrifice this creature: Search your library for a Spider Hero card, reveal it, put it into your hand, then shuffle. Activate only as a sorcery.

Plains

Mutavault

{T}: Add {C}.
{1}: This land becomes a 2/2 creature with all creature types until end of turn. It's still a land.

Spider-UK

Web-slinging {2}{W} (You may cast this spell for {2}{W} if you also return a tapped creature you control to its owner's hand.)
At the beginning of your end step, if two or more creatures entered the battlefield under your control this turn, you draw a card and gain 2 life.

Spider-Girl, Legacy Hero

During your turn, Spider-Girl has flying.
When Spider-Girl leaves the battlefield, create a 1/1 green and white Human Citizen creature token.

Twitching Doll

{T}: Add one mana of any color. Put a nest counter on this creature.
{T}, Sacrifice this creature: Create a 2/2 green Spider creature token with reach for each counter on this creature. Activate only as a sorcery.

Spider-Ham, Peter Porker

When Spider-Ham enters, create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this token: You gain 3 life.")
Animal May-Ham — Other Spiders, Boars, Bats, Bears, Birds, Cats, Dogs, Frogs, Jackals, Lizards, Mice, Otters, Rabbits, Raccoons, Rats, Squirrels, Turtles, and Wolves you control get +1/+1.

Spectacular Spider-Man

Flash
{1}: Spectacular Spider-Man gains flying until end of turn.
{1}, Sacrifice Spectacular Spider-Man: Creatures you control gain hexproof and indestructible until end of turn.

Silk, Web Weaver

Web-slinging {1}{G}{W} (You may cast this spell for {1}{G}{W} if you also return a tapped creature you control to its owner's hand.)
Whenever you cast a creature spell, create a 1/1 green and white Human Citizen creature token.
{3}{G}{W}: Creatures you control get +2/+2 and gain vigilance until end of turn.

Wall Crawl

When this enchantment enters, create a 2/1 green Spider creature token with reach, then you gain 1 life for each Spider you control.
Spiders you control get +1/+1 and can't be blocked by creatures with defender.

Aunt May

Whenever another creature you control enters, you gain 1 life. If it's a Spider, put a +1/+1 counter on it.

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.)

Roaming Throne

Ward {2}
As this creature enters, choose a creature type.
This creature 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.

Three Tree City

As Three Tree City enters, choose a creature type.
{T}: Add {C}.
{2}, {T}: Choose a color. Add an amount of mana of that color equal to the number of creatures you control of the chosen type.

Spider-Man India

Web-slinging {1}{G}{W} (You may cast this spell for {1}{G}{W} if you also return a tapped creature you control to its owner's hand.)
Pavitr's Sevā — Whenever you cast a creature spell, put a +1/+1 counter on target creature you control. It gains flying until end of turn.

Spinner of Souls

Reach
Whenever another nontoken creature you control dies, you may reveal cards from the top of your library until you reveal a creature card. Put that card into your hand and the rest on the bottom of your library in a random order.

Soulstone Sanctuary

{T}: Add {C}.
{4}: This land becomes a 3/3 creature with vigilance and all creature types. It's still a land.

Cavern of Souls

As this land enters, choose a creature type.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type, and that spell can't be countered.

Forest

Spiders-Man, Heroic Horde

Web-slinging {4}{G}{G} (You may cast this spell for {4}{G}{G} if you also return a tapped creature you control to its owner's hand.)
When Spiders-Man enters, if they were cast using web-slinging, you gain 3 life and create two 2/1 green Spider creature tokens with reach.