Sol'kanar the Swamp King

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)
Whenever a player casts a black spell, you gain 1 life.

Ghostly Changeling

Changeling (This card is every creature type.)
{1}{B}: Ghostly Changeling gets +1/+1 until end of turn.

Swamp Mosquito

Flying
Whenever Swamp Mosquito attacks and isn't blocked, defending player gets a poison counter. (A player with ten or more poison counters loses the game.)

God-Eternal Bontu

Menace
When God-Eternal Bontu enters, sacrifice any number of other permanents, then draw that many cards.
When God-Eternal Bontu dies or is put into exile from the battlefield, you may put it into its owner's library third from the top.

Mothdust Changeling

Changeling (This card is every creature type.)
Tap an untapped creature you control: Mothdust Changeling gains flying until end of turn.

Wardscale Crocodile

Hexproof (This creature can't be the target of spells or abilities your opponents control.)

Changeling Outcast

Changeling (This card is every creature type.)
Changeling Outcast can't block and can't be blocked.

Sewer Crocodile

{3}{U}: Sewer Crocodile can't be blocked this turn. This ability costs {3} less to activate if there are five or more mana values among cards in your graveyard.

Venomous Changeling

Changeling (This card is every creature type.)
Deathtouch

Sandbar Crocodile

Phasing (This phases in or out before you untap during each of your untap steps. While it's phased out, it's treated as though it doesn't exist.)

Catacomb Crocodile

Bontu's Last Reckoning

Destroy all creatures. Lands you control don't untap during your next untap step.

Bayou Dragonfly

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

Vivien's Crocodile

Vivien's Crocodile gets +1/+1 as long as you control a Vivien planeswalker.

Bontu the Glorified

Menace, indestructible
Bontu the Glorified can't attack or block unless a creature died under your control this turn.
{1}{B}, Sacrifice another creature: Scry 1. Each opponent loses 1 life and you gain 1 life.

Stonefare Crocodile

{2}{B}: Stonefare Crocodile gains lifelink until end of turn. (Damage dealt by this creature also causes you to gain that much life.)

Amoeboid Changeling

Changeling (This card is every creature type.)
{T}: Target creature gains all creature types until end of turn.
{T}: Target creature loses all creature types until end of turn.

Marsh Crocodile

When Marsh Crocodile enters, return a blue or black creature you control to its owner's hand.
When Marsh Crocodile enters, each player discards a card.

Rootwater Alligator

Sacrifice a Forest: Regenerate Rootwater Alligator.

Bayou Groff

As an additional cost to cast this spell, sacrifice a creature or pay {3}.

Moonglove Changeling

Changeling (This card is every creature type.)
{B}: Moonglove Changeling gains deathtouch until end of turn. (Any amount of damage it deals to a creature is enough to destroy that creature.)

Hagra Crocodile

Hagra Crocodile can't block.
Landfall — Whenever a land you control enters, Hagra Crocodile gets +2/+2 until end of turn.

Changeling Hero

Changeling (This card is every creature type.)
Champion a creature (When this enters, sacrifice it unless you exile another creature you control. When this leaves the battlefield, that card returns to the battlefield.)
Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Emperor Crocodile

When you control no other creatures, sacrifice Emperor Crocodile.

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.

Skeletal Crocodile

Woodland Changeling

Changeling (This card is every creature type.)

Injector Crocodile

When Injector Crocodile dies, incubate 3. (Create an Incubator token with three +1/+1 counters on it and "{2}: Transform this artifact." It transforms into a 0/0 Phyrexian artifact creature.)
Swampcycling {2} ({2}, Discard this card: Search your library for a Swamp card, reveal it, put it into your hand, then shuffle.)

Dross Crocodile

Veiled Crocodile

When a player has no cards in hand, if Veiled Crocodile is an enchantment, Veiled Crocodile becomes a 4/4 Crocodile creature.

Morophon, the Boundless

Changeling (This card is every creature type.)
As Morophon, the Boundless enters, choose a creature type.
Spells of the chosen type you cast cost {W}{U}{B}{R}{G} less to cast. This effect reduces only the amount of colored mana you pay.
Other creatures you control of the chosen type get +1/+1.

Crocodile of the Crossing

Haste
When Crocodile of the Crossing enters, put a -1/-1 counter on target creature you control.

Lurking Crocodile

Bloodthirst 1 (If an opponent was dealt damage this turn, this creature enters with a +1/+1 counter on it.)
Islandwalk (This creature can't be blocked as long as defending player controls an Island.)