Korlash, Heir to Blackblade

Korlash's power and toughness are each equal to the number of Swamps you control.
{1}{B}: Regenerate Korlash.
Grandeur — Discard another card named Korlash, Heir to Blackblade: Search your library for up to two Swamp cards, put them onto the battlefield tapped, then shuffle.

Corpse Connoisseur

When this creature enters, you may search your library for a creature card, put that card into your graveyard, then shuffle.
Unearth {3}{B} ({3}{B}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Veilborn Ghoul

This creature can't block.
Whenever a Swamp you control enters, you may return this card from your graveyard to your hand.

Primaris Eliminator

When this creature enters, choose one —
• Executioner Round — Destroy target creature.
• Hyperfrag Round — Creatures target player controls get -2/-2 until end of turn.

Phyrexian Delver

When this creature enters, return target creature card from your graveyard to the battlefield. You lose life equal to that card's mana value.

Vengeful Pharaoh

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
Whenever combat damage is dealt to you or a planeswalker you control, if this card is in your graveyard, destroy target attacking creature, then put this card on top of your library.

Sidisi, Undead Vizier

Deathtouch
Exploit (When this creature enters, you may sacrifice a creature.)
When Sidisi exploits a creature, you may search your library for a card, put it into your hand, then shuffle.

Woebearer

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
Whenever this creature deals combat damage to a player, you may return target creature card from your graveyard to your hand.

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.)