Diabolic Tutor

Search your library for a card, put that card into your hand, then shuffle.

Bontu's Monument

Black creature spells you cast cost {1} less to cast.
Whenever you cast a creature spell, each opponent loses 1 life and you gain 1 life.

Desecration Demon

Flying
At the beginning of each combat, any opponent may sacrifice a creature of their choice. If a player does, tap this creature and put a +1/+1 counter on it.

Deathmark

Expedition Map

{2}, {T}, Sacrifice this artifact: Search your library for a land card, reveal it, put it into your hand, then shuffle.

Sivriss, Nightmare Speaker

{T}, Sacrifice another creature or an artifact: For each opponent, you mill a card, then return that card from your graveyard to your hand unless that player pays 3 life. (To mill a card, put the top card of your library into your graveyard.)
Choose a Background (You can have a Background as a second commander.)

Swamp

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Horn of Greed

Whenever a player plays a land, that player draws a card.

Indulgent Tormentor

Flying
At the beginning of your upkeep, draw a card unless target opponent sacrifices a creature of their choice or pays 3 life.

Ob Nixilis Reignited

+1: You draw a card and you lose 1 life.
−3: Destroy target creature.
−8: Target opponent gets an emblem with "Whenever a player draws a card, you lose 2 life."

Trailblazer's Boots

Equipped creature has nonbasic landwalk. (It can't be blocked as long as defending player controls a nonbasic land.)
Equip {2}

Criminal Past

Commander creatures you own have menace and "This creature gets +X/+0, where X is the number of creature cards in your graveyard." (A creature with menace can't be blocked except by two or more creatures.)

Quest for the Gravelord

Whenever a creature dies, you may put a quest counter on Quest for the Gravelord.
Remove three quest counters from Quest for the Gravelord and sacrifice it: Create a 5/5 black Zombie Giant creature token.

Perpetual Timepiece

{T}: Mill two cards.
{2}, Exile Perpetual Timepiece: Shuffle any number of target cards from your graveyard into your library.

Liliana, Dreadhorde General

Whenever a creature you control dies, draw a card.
+1: Create a 2/2 black Zombie creature token.
−4: Each player sacrifices two creatures of their choice.
−9: Each opponent chooses a permanent they control of each permanent type and sacrifices the rest.

Mausoleum Secrets

Undergrowth — Search your library for a black card with mana value less than or equal to the number of creature cards in your graveyard, reveal it, put it into your hand, then shuffle.

Midnight Reaper

Whenever a nontoken creature you control dies, this creature deals 1 damage to you and you draw a card.