Imp's Mischief

Change the target of target spell with a single target. You lose life equal to that spell's mana value.

Vilis, Broker of Blood

Flying
{B}, Pay 2 life: Target creature gets -1/-1 until end of turn.
Whenever you lose life, draw that many cards. (Damage causes loss of life.)

Heartless Hidetsugu

{T}: Heartless Hidetsugu deals damage to each player equal to half that player's life total, rounded down.

Descent into Avernus

At the beginning of your upkeep, put two descent counters on this enchantment. Then each player creates X Treasure tokens and this enchantment deals X damage to each player, where X is the number of descent counters on this enchantment.

Sun Droplet

Whenever you're dealt damage, put that many charge counters on this artifact.
At the beginning of each upkeep, you may remove a charge counter from this artifact. If you do, you gain 1 life.

Nashi, Moon Sage's Scion

Ninjutsu {3}{B} ({3}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever Nashi deals combat damage to a player, exile the top card of each player's library. Until end of turn, you may play one of those cards. If you cast a spell this way, pay life equal to its mana value rather than paying its mana cost.

Ad Nauseam

Reveal the top card of your library and put that card into your hand. You lose life equal to its mana value. You may repeat this process any number of times.

Rowan, Scion of War

Menace
{T}: Spells you cast this turn that are black and/or red cost {X} less to cast, where X is the amount of life you lost this turn. Activate only as a sorcery.

Feed the Swarm

Destroy target creature or enchantment an opponent controls. You lose life equal to that permanent's mana value.

Antagonism

At the beginning of each player's end step, this enchantment deals 2 damage to that player unless one of their opponents was dealt damage this turn.

Earthquake

Earthquake deals X damage to each creature without flying and each player.

Reanimate

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

Crimson Honor Guard

Trample
At the beginning of each player's end step, this creature deals 4 damage to that player unless they control a commander.

Jackal Pup

Whenever this creature is dealt damage, it deals that much damage to you.

Keen Duelist

At the beginning of your upkeep, you and target opponent each reveal the top card of your library. You each lose life equal to the mana value of the card revealed by the other player. You each put the card you revealed into your hand.