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.

Symbiote Spawn

When this creature dies, each opponent loses 2 life and you gain 2 life.

Venomized Cat

Deathtouch
When this creature enters, mill two cards. (Put the top two cards of your library into your graveyard.)

Anticausal Vestige

When this creature leaves the battlefield, draw a card, then you may put a permanent card with mana value less than or equal to the number of lands you control from your hand onto the battlefield tapped.
Warp {4} (You may cast this card from your hand for its warp cost. Exile this creature at the beginning of the next end step, then you may cast it from exile on a later turn.)

Riveteers Ascendancy

Whenever you sacrifice a creature, you may return target creature card with lesser mana value from your graveyard to the battlefield tapped. Do this only once each turn.

Skithiryx, the Blight Dragon

Flying
Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
{B}: Skithiryx gains haste until end of turn.
{B}{B}: Regenerate Skithiryx.

Sol Ring

Diamond Weapon

This spell costs {1} less to cast for each permanent card in your graveyard.
Reach
Immune — Prevent all combat damage that would be dealt to Diamond Weapon.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Venom's Hunger

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

Venom, Lethal Protector

Menace, trample, haste
Whenever Venom attacks, you may sacrifice another creature. If you do, draw X cards, then you may put a permanent card with mana value X or less from your hand onto the battlefield, where X is the sacrificed creature's mana value.

Eddie Brock

When Eddie Brock enters, return target creature card with mana value 1 or less from your graveyard to the battlefield.
{3}{B}{R}{G}: Transform Eddie Brock. Activate only as a sorcery.

Eddie Brock // Venom, Lethal Protector

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}

Lethal Protection

Destroy target creature. Return up to one target creature card from your graveyard to your hand.

Venom, Eddie Brock

Menace (This creature can't be blocked except by two or more creatures.)
Whenever another creature dies, put a +1/+1 counter on Venom. If that creature was a Villain, draw a card.

Venom, Deadly Devourer

Vigilance, menace
{3}: Exile target creature card from a graveyard. When you do, put X +1/+1 counters on target Symbiote, where X is the exiled card's toughness.

Agent Venom

Flash
Menace
Whenever another nontoken creature you control dies, you draw a card and lose 1 life.

Behold the Sinister Six!

Return up to six target creature cards with different names from your graveyard to the battlefield.

Reanimate

Put target creature card from a graveyard onto the battlefield under your control. You lose life equal to that card's mana value.

Honest Rutstein

When Honest Rutstein enters, return target creature card from your graveyard to your hand.
Creature spells you cast cost {1} less to cast.