Desecrated Tomb

Whenever one or more creature cards leave your graveyard, create a 1/1 black Bat creature token with flying.

Mikaeus, the Unhallowed

Intimidate (This creature can't be blocked except by artifact creatures and/or creatures that share a color with it.)
Whenever a Human deals damage to you, destroy it.
Other non-Human creatures you control get +1/+1 and have undying. (When a creature with undying 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.)

Korvold, Fae-Cursed King

Flying
Whenever Korvold enters or attacks, sacrifice another permanent.
Whenever you sacrifice a permanent, put a +1/+1 counter on Korvold and draw a card.

Gray Merchant of Asphodel

When this creature enters, each opponent loses X life, where X is your devotion to black. You gain life equal to the life lost this way. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)

Elvish Mystic

Mana Matrix

Instant and enchantment spells you cast cost {2} less to cast.

Gamble

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

Agatha's Soul Cauldron

You may spend mana as though it were mana of any color to activate abilities of creatures you control.
Creatures you control with +1/+1 counters on them have all activated abilities of all creature cards exiled with Agatha's Soul Cauldron.
{T}: Exile target card from a graveyard. When a creature card is exiled this way, put a +1/+1 counter on target creature you control.

Deserted Temple

{T}: Add {C}.
{1}, {T}: Untap target land.

Mana Crypt

At the beginning of your upkeep, flip a coin. If you lose the flip, this artifact deals 3 damage to you.
{T}: Add {C}{C}.

Loxodon Warhammer

Equipped creature gets +3/+0 and has trample and lifelink.
Equip {3}

Elvish Visionary

Gravecrawler

This creature can't block.
You may cast this card from your graveyard as long as you control a Zombie.