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.

Spinneret and Spiderling

Whenever you attack with two or more Spiders, put a +1/+1 counter on Spinneret and Spiderling.
Whenever Spinneret and Spiderling deals 4 or more damage, exile the top card of your library. Until the end of your next turn, you may play that card.

Impostor Syndrome

Whenever a nontoken creature you control deals combat damage to a player, create a token that's a copy of it, except it isn't legendary.

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.

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.

Aunt May

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

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.

Scarlet Spider, Ben Reilly

Web-slinging {R}{G} (You may cast this spell for {R}{G} if you also return a tapped creature you control to its owner's hand.)
Trample
Sensational Save — If Scarlet Spider was cast using web-slinging, he enters with X +1/+1 counters on him, where X is the mana value of the returned creature.

Spider-Woman, Stunning Savior

Flying
Venom Blast — Artifacts and creatures your opponents control enter tapped.

Spider-Punk

Riot (This creature enters with your choice of a +1/+1 counter or haste.)
Other Spiders you control have riot.
Spells and abilities can't be countered.
Damage can't be prevented.

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.

Cosmic Spider-Man

Flying, first strike, trample, lifelink, haste
At the beginning of combat on your turn, other Spiders you control gain flying, first strike, trample, lifelink, and haste until end of turn.

Ultimate Spider-Man

First strike, haste
Camouflage — {2}: Put a +1/+1 counter on Ultimate Spider-Man. He gains hexproof and becomes colorless until end of turn.
Whenever you attack, double the number of each kind of counter on each Spider and legendary creature you control.

Miles Morales

When Miles Morales enters, put a +1/+1 counter on each of up to two target creatures.
{3}{R}{G}{W}: Transform Miles Morales. Activate only as a sorcery.

Miles Morales // Ultimate Spider-Man

Araña, Heart of the Spider

Whenever you attack, put a +1/+1 counter on target attacking creature.
Whenever a modified creature you control deals combat damage to a player, exile the top card of your library. You may play that card this turn. (Equipment, Auras you control, and counters are modifications.)

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.

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.

Spider-Man 2099, Miguel O'Hara

When Spider-Man 2099 enters, return up to one target creature to its owner's hand.
Whenever one or more creatures you control deal combat damage to a player, draw a card.

Spider-Man, Miles Morales

Vigilance, trample (Attacking doesn't cause this creature to tap. He can deal excess combat damage to the player he's attacking.)
Whenever Spider-Man enters or attacks, put a +1/+1 counter on each other creature you control. Those creatures gain trample until end of turn.

Gwenom, Remorseless

Deathtouch, lifelink
Whenever Gwenom attacks, until end of turn you may look at the top card of your library any time and you may play cards from the top of your library. If you cast a spell this way, pay life equal to its mana value rather than pay its mana cost.