
Electro, Assaulting Battery | Legendary Creature | Human Villain | Flying
You don't lose unspent red mana as steps and phases end.
Whenever you cast an instant or sorcery spell, add {R}.
When Electro leaves the battlefield, you may pay {X}. When you do, he deals X damage to target player. | Dmitry Burmak

Spider-Punk | Legendary Creature | Spider Human Hero | 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. | Vincent Proce

Maximum Carnage | Enchantment | Saga | (As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Until your next turn, each creature attacks each combat if able and attacks a player other than you if able.
II — Add {R}{R}{R}.
III — This Saga deals 5 damage to each opponent. | Tiffany Turrill

J. Jonah Jameson | Legendary Creature | Human Citizen | When J. Jonah Jameson enters, suspect up to one target creature.
Whenever a creature you control with menace attacks, create a Treasure token. | Olivier Bernard

Shadow of the Goblin | Enchantment | | Unreliable Visions — At the beginning of your first main phase, discard a card. If you do, draw a card.
Undying Vengeance — Whenever you play a land or cast a spell from anywhere other than your hand, this enchantment deals 1 damage to each opponent. | Dallas Williams

Spinneret and Spiderling | Legendary Creature | Spider Human Hero | 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. | Igor Krstic

Araña, Heart of the Spider | Legendary Creature | Spider Human Hero | 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.) | Alexander Mokhov

Spider-Man 2099 | Legendary Creature | Spider Human Hero | From the Future — You can't cast Spider-Man 2099 during your first, second, or third turns of the game.
Double strike, vigilance
At the beginning of your end step, if you've played a land or cast a spell this turn from anywhere other than your hand, Spider-Man 2099 deals damage equal to his power to any target. | Slawomir Maniak

Carnage, Crimson Chaos | Legendary Creature | Symbiote Villain | Trample
When Carnage enters, return target creature card with mana value 3 or less from your graveyard to the battlefield. It gains "This creature attacks each combat if able" and "When this creature deals combat damage to a player, sacrifice it."
Mayhem {B}{R} | Diana Franco

Ultimate Green Goblin | Legendary Creature | Goblin Villain | At the beginning of your upkeep, discard a card, then create a Treasure token.
Mayhem {2}{B/R} (You may cast this card from your graveyard for {2}{B/R} if you discarded it this turn. Timing rules still apply.) | Caio Cacau

Scarlet Spider, Ben Reilly | Legendary Creature | Spider Human Hero | 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. | Alexandre Honoré

Cheering Crowd | Creature | Human Citizen | At the beginning of each player's first main phase, that player may put a +1/+1 counter on this creature. If they do, they add {C} for each counter on it. | Deruchenko Alexander

Oscorp Industries | Land | | This land enters tapped.
When this land enters from a graveyard, you lose 2 life.
{T}: Add {U}, {B}, or {R}.
Mayhem (You may play this card from your graveyard if you discarded it this turn. Timing rules still apply.) | Francisco Badilla