Syr Konrad, the Grim

Whenever another creature dies, or a creature card is put into a graveyard from anywhere other than the battlefield, or a creature card leaves your graveyard, Syr Konrad, the Grim deals 1 damage to each opponent.
{1}{B}: Each player mills a card. (They each put the top card of their library into their graveyard.)

Duplicant

Imprint — When Duplicant enters the battlefield, you may exile target nontoken creature.
As long as a card exiled with Duplicant is a creature card, Duplicant has the power, toughness, and creature types of the last creature card exiled with Duplicant. It's still a Shapeshifter.

Throne of Eldraine

As Throne of Eldraine enters the battlefield, choose a color.
{T}: Add four mana of the chosen color. Spend this mana only to cast monocolored spells of that color.
{3}, {T}: Draw two cards. Spend only mana of the chosen color to activate this ability.

Ovalchase Daredevil

Whenever an artifact enters the battlefield under your control, you may return Ovalchase Daredevil from your graveyard to your hand.

Soul Enervation

Flash
When Soul Enervation enters the battlefield, target creature gets -4/-4 until end of turn.
Whenever one or more creature cards leave your graveyard, each opponent loses 1 life and you gain 1 life.

Sceptre of Eternal Glory

{T}: Add one mana of any color.
{T}: Add three mana of any one color. Activate only if you control three or more lands with the same name.

Tortured Existence

{B}, Discard a creature card: Return target creature card from your graveyard to your hand.

Leaden Myr

Imotekh the Stormlord

Phaeron — Whenever one or more artifact cards leave your graveyard, create two 2/2 black Necron Warrior artifact creature tokens.
Grand Strategist — At the beginning of combat on your turn, another target artifact creature you control gets +2/+2 and gains menace until end of turn.

Meteor Golem

When Meteor Golem enters the battlefield, destroy target nonland permanent an opponent controls.

Canoptek Spyder

Flying
Fabricator Claw Array — Whenever another nontoken artifact creature or Vehicle enters the battlefield under your control, draw a card.

Desecrated Tomb

Whenever one or more creature cards leave your graveyard, create a 1/1 black Bat creature token with flying.

Noxious Gearhulk

Menace
When Noxious Gearhulk enters the battlefield, you may destroy another target creature. If a creature is destroyed this way, you gain life equal to its toughness.

Necron Deathmark

Flash
Synaptic Disintegrator — When Necron Deathmark enters the battlefield, destroy up to one target creature and target player mills three cards.