Swamp

Rathi Intimidator

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
{2}, {T}: Search your library for a Mercenary permanent card with mana value 2 or less, put it onto the battlefield, then shuffle.

Cateran Slaver

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)
{5}, {T}: Search your library for a Mercenary permanent card with mana value 5 or less, put it onto the battlefield, then shuffle.

Mercenary Knight

When Mercenary Knight enters the battlefield, sacrifice it unless you discard a creature card.

Cateran Enforcer

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
{4}, {T}: Search your library for a Mercenary permanent card with mana value 4 or less, put it onto the battlefield, then shuffle.

Silent Assassin

{3}{B}: Destroy target blocking creature at end of combat.

Phyrexian Driver

When Phyrexian Driver enters the battlefield, other Mercenary creatures get +1/+1 until end of turn.

Highway Robber

When Highway Robber enters the battlefield, target opponent loses 2 life and you gain 2 life.

Cateran Persuader

{1}, {T}: Search your library for a Mercenary permanent card with mana value 1 or less, put it onto the battlefield, then shuffle.

Crypt Ghast

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.)
Whenever you tap a Swamp for mana, add an additional {B}.

Cateran Kidnappers

{3}, {T}: Search your library for a Mercenary permanent card with mana value 3 or less, put it onto the battlefield, then shuffle.

Cateran Brute

{2}, {T}: Search your library for a Mercenary permanent card with mana value 2 or less, put it onto the battlefield, then shuffle.

Cateran Summons

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

Dauthi Mercenary

Shadow (This creature can block or be blocked by only creatures with shadow.)
{1}{B}: Dauthi Mercenary gets +1/+0 until end of turn.

Phyrexian Prowler

Fading 3 (This creature enters the battlefield with three fade counters on it. At the beginning of your upkeep, remove a fade counter from it. If you can't, sacrifice it.)
Remove a fade counter from Phyrexian Prowler: Phyrexian Prowler gets +1/+1 until end of turn.

Ascendant Evincar

Flying (This creature can't be blocked except by creatures with flying or reach.)
Other black creatures get +1/+1.
Nonblack creatures get -1/-1.

Sol Ring

K'rrik, Son of Yawgmoth

({B/P} can be paid with either {B} or 2 life.)
Lifelink
For each {B} in a cost, you may pay 2 life rather than pay that mana.
Whenever you cast a black spell, put a +1/+1 counter on K'rrik, Son of Yawgmoth.

Death Charmer

Whenever Death Charmer deals combat damage to a creature, that creature's controller loses 2 life unless they pay {2}.

Bog Glider

Flying
{T}, Sacrifice a land: Search your library for a Mercenary permanent card with mana value 2 or less, put it onto the battlefield, then shuffle.

Rathi Fiend

When Rathi Fiend enters the battlefield, each player loses 3 life.
{3}, {T}: Search your library for a Mercenary permanent card with mana value 3 or less, put it onto the battlefield, then shuffle.

Gray Merchant of Asphodel

When Gray Merchant of Asphodel enters the battlefield, 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.)

Bog Smugglers

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)

Strongarm Thug

When Strongarm Thug enters the battlefield, you may return target Mercenary card from your graveyard to your hand.

Doomed Necromancer

{B}, {T}, Sacrifice Doomed Necromancer: Return target creature card from your graveyard to the battlefield.

Rathi Assassin

{1}{B}{B}, {T}: Destroy target tapped nonblack creature.
{3}, {T}: Search your library for a Mercenary permanent card with mana value 3 or less, put it onto the battlefield, then shuffle.

Cateran Overlord

Sacrifice a creature: Regenerate Cateran Overlord.
{6}, {T}: Search your library for a Mercenary permanent card with mana value 6 or less, put it onto the battlefield, then shuffle.