Giant Cindermaw

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
Players can't gain life.

Magmakin Artillerist

Whenever you discard one or more cards, this creature deals that much damage to each opponent.
Cycling {1}{R} ({1}{R}, Discard this card: Draw a card.)
When you cycle this card, it deals 1 damage to each opponent.

Swarm, Being of Bees

Flash
Flying
Mayhem {B} (You may cast this card from your graveyard for {B} if you discarded it this turn. Timing rules still apply.)

Swamp

Green Goblin, Revenant

Flying, deathtouch
Whenever Green Goblin attacks, discard a card. Then draw a card for each card you've discarded this turn.

Scarlet Spider, Kaine

Menace (This creature can't be blocked except by two or more creatures.)
When Scarlet Spider enters, you may discard a card. If you do, put a +1/+1 counter on him.
Mayhem {B/R} (You may cast this card from your graveyard for {B/R} if you discarded it this turn. Timing rules still apply.)

Massacre Wurm

When this creature enters, creatures your opponents control get -2/-2 until end of turn.
Whenever a creature an opponent controls dies, that player loses 2 life.

Shriek, Treblemaker

At the beginning of your first main phase, you may discard a card. When you do, target creature can't block this turn.
Sonic Blast — Whenever a creature an opponent controls dies, Shriek deals 1 damage to that player.

Reassembling Skeleton

{1}{B}: Return this card from your graveyard to the battlefield tapped.

Alesha, Who Laughs at Fate

First strike
Whenever Alesha attacks, put a +1/+1 counter on it.
Raid — At the beginning of your end step, if you attacked this turn, return target creature card with mana value less than or equal to Alesha's power from your graveyard to the battlefield.

Hero's Downfall

Masked Meower

Haste
Discard a card, Sacrifice this creature: Draw a card.

Duress

Target opponent reveals their hand. You choose a noncreature, nonland card from it. That player discards that card.

Inner Demons Gangsters

Discard a card: This creature gets +1/+0 and gains menace until end of turn. Activate only as a sorcery. (It can't be blocked except by two or more creatures.)

Spider-Islanders

Mayhem {1}{R} (You may cast this card from your graveyard for {1}{R} if you discarded it this turn. Timing rules still apply.)

Undying Malice

Until end of turn, target creature gains "When this creature dies, return it to the battlefield tapped under its owner's control with a +1/+1 counter on it."

Shock

Venom, Evil Unleashed

Deathtouch
{2}{B}, Exile this card from your graveyard: Put two +1/+1 counters on target creature. It gains deathtouch until end of turn. Activate only as a sorcery.

Phyrexian Arena

At the beginning of your upkeep, you draw a card and you lose 1 life.

Pumpkin Bombardment

As an additional cost to cast this spell, discard a card or pay {2}.
Pumpkin Bombardment deals 3 damage to target creature.

Scorpion's Sting

Target creature gets -3/-3 until end of turn.

Vengeful Bloodwitch

Whenever this creature or another creature you control dies, target opponent loses 1 life and you gain 1 life.

Venom's Hunger

This spell costs {2} less to cast if you control a Villain.
Destroy target creature. You gain 2 life.

Spider-Gwen, Free Spirit

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

Mountain

Electro's Bolt

Electro's Bolt deals 4 damage to target creature.
Mayhem {1}{R} (You may cast this card from your graveyard for {1}{R} if you discarded it this turn. Timing rules still apply.)

Risky Research

Surveil 2, then draw two cards. You lose 2 life. (To surveil 2, look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)