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.)

Alien Symbiosis

Enchant creature
Enchanted creature gets +1/+1, has menace, and is a Symbiote in addition to its other types.
You may cast this card from your graveyard by discarding a card in addition to paying its other costs.

Dogged Detective

When this creature enters, 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.)
Whenever an opponent draws their second card each turn, you may return this card from your graveyard to your hand.

Sanitarium Skeleton

{2}{B}: Return this card from your graveyard to your hand.

The Death of Gwen Stacy

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Destroy target creature.
II — Each player may discard a card. Each player who doesn't loses 3 life.
III — Exile any number of target players' graveyards.

Pumpkin Bombardment

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

Monument to Endurance

Whenever you discard a card, choose one that hasn't been chosen this turn —
• Draw a card.
• Create a Treasure token.
• Each opponent loses 3 life.

Shadow of the Goblin

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.

Ultimate Green Goblin

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.)

Carnage, Crimson Chaos

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}

Squee, Goblin Nabob

At the beginning of your upkeep, you may return this card from your graveyard to your hand.

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.)

Sandman's Quicksand

Mayhem {3}{B} (You may cast this card from your graveyard for {3}{B} if you discarded it this turn. Timing rules still apply.)
All creatures get -2/-2 until end of turn. If this spell's mayhem cost was paid, creatures your opponents control get -2/-2 until end of turn instead.

Gutterbones

This creature enters tapped.
{1}{B}: Return this card from your graveyard to your hand. Activate only during your turn and only if an opponent lost life 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.)

Raging Goblinoids

Haste
Mayhem {2}{R} (You may cast this card from your graveyard for {2}{R} if you discarded it this turn. Timing rules still apply.)