Belbe, Corrupted Observer

At the beginning of each postcombat main phase, the active player adds {C}{C} for each of your opponents who lost life this turn. (Damage causes loss of life.)

Tainted Wood

{T}: Add {C}.
{T}: Add {B} or {G}. Activate only if you control a Swamp.

Archers' Parapet

Defender
{1}{B}, {T}: Each opponent loses 1 life.

Loyal Subordinate

Menace (This creature can't be blocked except by two or more creatures.)
Lieutenant — At the beginning of combat on your turn, if you control your commander, each opponent loses 3 life.

Llanowar Wastes

{T}: Add {C}.
{T}: Add {B} or {G}. Llanowar Wastes deals 1 damage to you.

Festering Gulch

Festering Gulch enters tapped.
When Festering Gulch enters, it deals 1 damage to target opponent.
{T}: Add {B} or {G}.

Command Tower

{T}: Add one mana of any color in your commander's color identity.

Leechridden Swamp

({T}: Add {B}.)
Leechridden Swamp enters tapped.
{B}, {T}: Each opponent loses 1 life. Activate only if you control two or more black permanents.

Infested Thrinax

Flash
When Infested Thrinax enters, until end of turn, whenever a nontoken creature you control dies, create a number of 1/1 green Saproling creature tokens equal to that creature's power.

Maggot Carrier

When Maggot Carrier enters, each player loses 1 life.

Pulse Tracker

Whenever Pulse Tracker attacks, each opponent loses 1 life.

Exotic Orchard

{T}: Add one mana of any color that a land an opponent controls could produce.

Hooded Blightfang

Deathtouch
Whenever a creature you control with deathtouch attacks, each opponent loses 1 life and you gain 1 life.
Whenever a creature you control with deathtouch deals damage to a planeswalker, destroy that planeswalker.

Thornbow Archer

Whenever Thornbow Archer attacks, each opponent who doesn't control an Elf loses 1 life.

Temple of Malady

Temple of Malady enters tapped.
When Temple of Malady enters, scry 1.
{T}: Add {B} or {G}.

Thieving Amalgam

At the beginning of each opponent's upkeep, you manifest the top card of that player's library. (Put it onto the battlefield face down as a 2/2 creature. Turn it face up any time for its mana cost if it's a creature card.)
Whenever a creature you control but don't own dies, its owner loses 2 life and you gain 2 life.

Vicious Conquistador

Whenever Vicious Conquistador attacks, each opponent loses 1 life.

Basilica Screecher

Flying
Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)

Vampire Neonate

{2}, {T}: Each opponent loses 1 life and you gain 1 life.

Plague Spitter

At the beginning of your upkeep, Plague Spitter deals 1 damage to each creature and each player.
When Plague Spitter dies, it deals 1 damage to each creature and each player.

Night Market Lookout

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

Mardu Shadowspear

Whenever Mardu Shadowspear attacks, each opponent loses 1 life.
Dash {1}{B} (You may cast this spell for its dash cost. If you do, it gains haste, and it's returned from the battlefield to its owner's hand at the beginning of the next end step.)