Putrid Imp

Discard a card: Putrid Imp gains flying until end of turn.
Threshold — As long as seven or more cards are in your graveyard, Putrid Imp gets +1/+1 and can't block.

Animate Dead

Enchant creature card in a graveyard
When Animate Dead enters, if it's on the battlefield, it loses "enchant creature card in a graveyard" and gains "enchant creature put onto the battlefield with Animate Dead." Return enchanted creature card to the battlefield under your control and attach Animate Dead to it. When Animate Dead leaves the battlefield, that creature's controller sacrifices it.
Enchanted creature gets -1/-0.

Visara the Dreadful

Flying
{T}: Destroy target creature. It can't be regenerated.

Merfolk Looter

Careful Study

Duress

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

Exhume

Each player puts a creature card from their graveyard onto the battlefield.

Verdant Force

At the beginning of each upkeep, create a 1/1 green Saproling creature token.

Swamp

Buried Alive

Search your library for up to three creature cards, put them into your graveyard, then shuffle.

Symbiotic Wurm

When Symbiotic Wurm dies, create seven 1/1 green Insect creature tokens.

Underground River

{T}: Add {C}.
{T}: Add {U} or {B}. Underground River deals 1 damage to you.

Reanimate

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

Akroma, Angel of Wrath

Flying, first strike, vigilance, trample, haste, protection from black and from red

Dark Ritual

Tainted Isle

{T}: Add {C}.
{T}: Add {U} or {B}. Activate only if you control a Swamp.

Lotus Petal

{T}, Sacrifice Lotus Petal: Add one mana of any color.

Island

Cabal Therapy

Choose a nonland card name. Target player reveals their hand and discards all cards with that name.
Flashback—Sacrifice a creature. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Sickening Dreams

As an additional cost to cast this spell, discard X cards.
Sickening Dreams deals X damage to each creature and each player.

Phantom Nishoba

Trample
Phantom Nishoba enters with seven +1/+1 counters on it.
Whenever Phantom Nishoba deals damage, you gain that much life.
If damage would be dealt to Phantom Nishoba, prevent that damage. Remove a +1/+1 counter from Phantom Nishoba.