Starling, Aerial Ally

Flying
When Starling enters, another target creature you control gains flying until end of turn.

Web-Warriors

When this creature enters, put a +1/+1 counter on each other creature you control.

University Campus

This land enters tapped.
{T}: Add {W} or {U}.
{4}, {T}: Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

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.

Wraith, Vicious Vigilante

Double strike
Fear Gas — Wraith can't be blocked.

Silver Sable, Mercenary Leader

When Silver Sable enters, put a +1/+1 counter on another target creature.
Whenever Silver Sable attacks, target modified creature you control gains lifelink until end of turn. (Equipment, Auras you control, and counters are modifications.)

Island

Mary Jane Watson

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

Whoosh!

Kicker {1}{U} (You may pay an additional {1}{U} as you cast this spell.)
Return target nonland permanent to its owner's hand. If this spell was kicked, draw a card.

Urban Retreat

This land enters tapped.
{T}: Add {G}, {W}, or {U}.
{2}, Return a tapped creature you control to its owner's hand: Put this card from your hand onto the battlefield. Activate only as a sorcery.

Origin of Spider-Man

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Create a 2/1 green Spider creature token with reach.
II — Put a +1/+1 counter on target creature you control. It becomes a legendary Spider Hero in addition to its other types.
III — Target creature you control gains double strike until end of turn.

Spider-Byte, Web Warden

When Spider-Byte enters, return up to one target nonland permanent to its owner's hand.

Spider-Man, Web-Slinger

Web-slinging {W} (You may cast this spell for {W} if you also return a tapped creature you control to its owner's hand.)

Web Up

When this enchantment enters, exile target nonland permanent an opponent controls until this enchantment leaves the battlefield.

City Pigeon

Flying
When this creature leaves the battlefield, create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this token: You gain 3 life.")

Amazing Acrobatics

Choose one or both —
• Counter target spell.
• Tap one or two target creatures.

Plains

Wild Pack Squad

At the beginning of combat on your turn, up to one target creature gains first strike and vigilance until end of turn.

Spider-Man No More

Enchant creature
Enchanted creature is a Citizen with base power and toughness 1/1. It has defender and loses all other abilities. (It also loses all other creature types.)

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.

Spectacular Tactics

Choose one —
• Put a +1/+1 counter on target creature you control. It gains hexproof until end of turn.
• Destroy target creature with power 4 or greater.

Skyward Spider

Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
This creature has flying as long as it's modified. (Equipment, Auras you control, and counters are modifications.)

Aunt May

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