Starling, Aerial Ally

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

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.

Spider-Gwen, Free Spirit

Reach
Whenever Spider-Gwen becomes tapped, you may discard a card. If you do, draw a card.

Bagel and Schmear

Share — {W}, {T}, Sacrifice this artifact: Put a +1/+1 counter on up to one target creature. Draw a card. Activate only as a sorcery.
Nosh — {2}, {T}, Sacrifice this artifact: You gain 3 life and draw a card.

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.)

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.

Living Brain, Mechanical Marvel

At the beginning of combat on your turn, target non-Equipment artifact you control becomes an artifact creature with base power and toughness 3/3 until end of turn. Untap it.

Iron Spider, Stark Upgrade

Vigilance
{T}: Put a +1/+1 counter on each artifact creature and/or Vehicle you control.
{2}, Remove two +1/+1 counters from among artifacts you control: Draw a card.

Arachne, Psionic Weaver

Web-slinging {W} (You may cast this spell for {W} if you also return a tapped creature you control to its owner's hand.)
As Arachne enters, look at an opponent's hand, then choose a card type other than creature.
Spells of the chosen type cost {1} more to cast.

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.)

Angry Rabble

Trample
Whenever you cast a spell with mana value 4 or greater, this creature deals 1 damage to each opponent.
{5}{R}: Put two +1/+1 counters on this creature. Activate only as a sorcery.

Aunt May

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

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.

Molten Man, Inferno Incarnate

When Molten Man enters, search your library for a basic Mountain card, put it onto the battlefield tapped, then shuffle.
Molten Man gets +1/+1 for each Mountain you control.
When Molten Man leaves the battlefield, sacrifice a land.