The Soul Stone

Indestructible
{T}: Add {B}.
{6}{B}, {T}, Exile a creature you control: Harness The Soul Stone. (Once harnessed, its ∞ ability is active.)
∞ — At the beginning of your upkeep, return target creature card from your graveyard to the battlefield.

Urborg, Tomb of Yawgmoth

Each land is a Swamp in addition to its other land types.

Swamp

Sol Ring

Golgari Signet

Lethal Protection

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

Symbiote Spawn

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

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}

Chromatic Lantern

Lands you control have "{T}: Add one mana of any color."
{T}: Add one mana of any color.

Talisman of Resilience

{T}: Add {C}.
{T}: Add {B} or {G}. This artifact deals 1 damage to you.

Scorpion, Seething Striker

Deathtouch
At the beginning of your end step, if a creature died this turn, target creature you control connives. (Draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on that creature.)

Thought Vessel

You have no maximum hand size.
{T}: Add {C}.

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.

Bayou

Worn Powerstone

This artifact enters tapped.
{T}: Add {C}{C}.

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice this artifact: Draw a card.

Urza's Incubator

As this artifact enters, choose a creature type.
Creature spells of the chosen type cost {2} less to cast.

Arcane Signet

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

Liquimetal Torque

{T}: Add {C}.
{T}: Target nonland permanent becomes an artifact in addition to its other types until end of turn.

Scorpion's Sting

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

Herald's Horn

As this artifact enters, choose a creature type.
Creature spells you cast of the chosen type cost {1} less to cast.
At the beginning of your upkeep, look at the top card of your library. If it's a creature card of the chosen type, you may reveal it and put it into your hand.

Forest

Venom's Hunger

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

Eerie Gravestone

When this artifact enters, draw a card.
{1}{B}, Sacrifice this artifact: Mill four cards. You may put a creature card from among them into your hand. (To mill four cards, put the top four cards of your library into your graveyard.)

Grendel, Spawn of Knull

Flying (This creature can't be blocked except by creatures with flying or reach.)
Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

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

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.

Gwenom, Remorseless

Deathtouch, lifelink
Whenever Gwenom attacks, until end of turn, you may look at the top card of your library any time and you may play cards from the top of your library. If you cast a spell this way, pay life equal to its mana value rather than pay its mana cost.

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.

Symbiote Spider-Man

Whenever this creature deals combat damage to a player, look at that many cards from the top of your library. Put one of them into your hand and the rest into your graveyard.
Find New Host — {2}{U/B}, Exile this card from your graveyard: Put a +1/+1 counter on target creature you control. It gains this card's other abilities. Activate only as a sorcery.