Swamp

Deathgreeter

Whenever another creature dies, you may gain 1 life.

Viscera Seer

Sacrifice a creature: Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Vampiric Link

Enchant creature
Whenever enchanted creature deals damage, you gain that much life.

Innocent Blood

Each player sacrifices a creature of their choice.

Tragic Slip

Target creature gets -1/-1 until end of turn.
Morbid — That creature gets -13/-13 until end of turn instead if a creature died this turn.

Duress

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

Fanatical Offering

As an additional cost to cast this spell, sacrifice an artifact or creature.
Draw two cards and create a Map token. (It's an artifact with "{1}, {T}, Sacrifice this artifact: Target creature you control explores. Activate only as a sorcery.")

Lampad of Death's Vigil

{1}, Sacrifice a creature: Each opponent loses 1 life and you gain 1 life.

Carrion Feeder

Carrion Feeder can't block.
Sacrifice a creature: Put a +1/+1 counter on Carrion Feeder.

Plains

Seal of Cleansing

Sacrifice Seal of Cleansing: Destroy target artifact or enchantment.

Doomed Traveler

When Doomed Traveler dies, create a 1/1 white Spirit creature token with flying.

Leave No Trace

Radiance — Destroy target enchantment and each other enchantment that shares a color with it.

Castigate

Target opponent reveals their hand. You choose a nonland card from it and exile that card.

Village Rites

As an additional cost to cast this spell, sacrifice a creature.
Draw two cards.

Mortician Beetle

Whenever a player sacrifices a creature, you may put a +1/+1 counter on Mortician Beetle.

Myr Servitor

At the beginning of your upkeep, if Myr Servitor is on the battlefield, each player returns all cards named Myr Servitor from their graveyard to the battlefield.

Ninth Bridge Patrol

Whenever another creature you control leaves the battlefield, put a +1/+1 counter on Ninth Bridge Patrol.

Fungal Infection

Target creature gets -1/-1 until end of turn. Create a 1/1 green Saproling creature token.

Ash Barrens

{T}: Add {C}.
Basic landcycling {1} ({1}, Discard this card: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.)

Hunted Witness

When Hunted Witness dies, create a 1/1 white Soldier creature token with lifelink.