Sovereign's Bite

Target player loses 3 life and you gain 3 life.

Geralf's Messenger

Geralf's Messenger enters the battlefield tapped.
When Geralf's Messenger enters the battlefield, target opponent loses 2 life.
Undying (When this creature dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)

Trespasser's Curse

Enchant player
Whenever a creature enters the battlefield under enchanted player's control, that player loses 1 life and you gain 1 life.

Swamp

Bump in the Night

Target opponent loses 3 life.
Flashback {5}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Vampire Cutthroat

Skulk (This creature can't be blocked by creatures with greater power.)
Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Dark Ritual

Sign in Blood

Target player draws two cards and loses 2 life.

Songs of the Damned

Add {B} for each creature card in your graveyard.

Serrated Scorpion

When Serrated Scorpion dies, it deals 2 damage to each opponent and you gain 2 life.

Cauldron Familiar

When Cauldron Familiar enters the battlefield, each opponent loses 1 life and you gain 1 life.
Sacrifice a Food: Return Cauldron Familiar from your graveyard to the battlefield.

Collective Brutality

Escalate—Discard a card. (Pay this cost for each mode chosen beyond the first.)
Choose one or more —
• Target opponent reveals their hand. You choose an instant or sorcery card from it. That player discards that card.
• Target creature gets -2/-2 until end of turn.
• Target opponent loses 2 life and you gain 2 life.

Night Market Lookout

Whenever Night Market Lookout becomes tapped, each opponent loses 1 life and you gain 1 life.