Underground Sea

Entomb

Search your library for a card, put that card into your graveyard, then shuffle.

Dark Ritual

Polluted Delta

{T}, Pay 1 life, Sacrifice Polluted Delta: Search your library for an Island or Swamp card, put it onto the battlefield, then shuffle.

Swamp

Thoughtseize

Target player reveals their hand. You choose a nonland card from it. That player discards that card. You lose 2 life.

Damnation

Destroy all creatures. They can't be regenerated.

Go for the Throat

Unmarked Grave

Search your library for a nonlegendary card, put that card into your graveyard, then shuffle.

Reanimate

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

Lotus Petal

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

Prized Amalgam

Whenever a creature enters, if it entered from your graveyard or you cast it from your graveyard, return Prized Amalgam from your graveyard to the battlefield tapped at the beginning of the next end step.

Consider

Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)
Draw a card.

Dance of the Dead

Enchant creature card in a graveyard
When Dance of the 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 Dance of the Dead." Put enchanted creature card onto the battlefield tapped under your control and attach Dance of the Dead to it. When Dance of the Dead leaves the battlefield, that creature's controller sacrifices it.
Enchanted creature gets +1/+1 and doesn't untap during its controller's untap step.
At the beginning of the upkeep of enchanted creature's controller, that player may pay {1}{B}. If the player does, untap that creature.

Careful Study

Inkwell Leviathan

Trample
Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Shroud (This creature can't be the target of spells or abilities.)

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.

Buried Alive

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