Island Fish Jasconius

Island Fish Jasconius doesn't untap during your untap step.
At the beginning of your upkeep, you may pay {U}{U}{U}. If you do, untap Island Fish Jasconius.
Island Fish Jasconius can't attack unless defending player controls an Island.
When you control no Islands, sacrifice Island Fish Jasconius.

Ravenous Gigantotherium

Devour 3 (As this enters, you may sacrifice any number of creatures. This creature enters with three times that many +1/+1 counters on it.)
When Ravenous Gigantotherium enters, it deals X damage divided as you choose among up to X target creatures, where X is its power. Each of those creatures deals damage equal to its power to Ravenous Gigantotherium.

Rimehorn Aurochs

Trample
Whenever Rimehorn Aurochs attacks, it gets +1/+0 until end of turn for each other attacking Aurochs.
{2}{S}: Target creature blocks target creature this turn if able. ({S} can be paid with one mana from a snow source.)

Ovinize

Until end of turn, target creature loses all abilities and has base power and toughness 0/1.

Gurzigost

At the beginning of your upkeep, sacrifice Gurzigost unless you put two cards from your graveyard on the bottom of your library.
{G}{G}, Discard a card: You may have Gurzigost assign its combat damage this turn as though it weren't blocked.

Scragnoth

This spell can't be countered.
Protection from blue

Saprazzan Legate

If an opponent controls a Mountain and you control an Island, you may cast this spell without paying its mana cost.
Flying

Blight-Breath Catoblepas

When Blight-Breath Catoblepas enters, target creature an opponent controls gets -X/-X until end of turn, where X is your devotion to black. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)

Ring of Xathrid

{2}: Regenerate equipped creature. (The next time that creature would be destroyed this turn, instead tap it, remove it from combat, and heal all damage on it.)
At the beginning of your upkeep, put a +1/+1 counter on equipped creature if it's black.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Mwonvuli Ooze

Cumulative upkeep {2} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay {2} for each age counter on it.)
Mwonvuli Ooze's power and toughness are each equal to 1 plus twice the number of age counters on it.

Loathsome Catoblepas

{2}{G}: Loathsome Catoblepas must be blocked this turn if able.
When Loathsome Catoblepas dies, target creature an opponent controls gets -3/-3 until end of turn.

Erithizon

Whenever Erithizon attacks, put a +1/+1 counter on target creature of defending player's choice.

Phthisis

Destroy target creature. Its controller loses life equal to its power plus its toughness.
Suspend 5—{1}{B} (Rather than cast this card from your hand, you may pay {1}{B} and exile it with five time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)

Vigean Hydropon

Graft 5 (This creature enters with five +1/+1 counters on it. Whenever another creature enters, you may move a +1/+1 counter from this creature onto it.)
Vigean Hydropon can't attack or block.

Pyxis of Pandemonium

{T}: Each player exiles the top card of their library face down.
{7}, {T}, Sacrifice Pyxis of Pandemonium: Each player turns face up all cards they own exiled with Pyxis of Pandemonium, then puts all permanent cards among them onto the battlefield.

Hyalopterous Lemure

{0}: Hyalopterous Lemure gets -1/-0 and gains flying until end of turn.

Grollub

Whenever Grollub is dealt damage, each opponent gains that much life.

Skithiryx, the Blight Dragon

Flying
Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
{B}: Skithiryx, the Blight Dragon gains haste until end of turn.
{B}{B}: Regenerate Skithiryx.

Stratozeppelid

Flying
Stratozeppelid can block only creatures with flying.

Swamp

Halcyon Glaze

Whenever you cast a creature spell, Halcyon Glaze becomes a 4/4 Illusion creature with flying in addition to its other types until end of turn.

River Hoopoe

Flying
{3}{G}{U}: You gain 2 life and draw a card.

Phyrexian Scuta

Kicker—Pay 3 life. (You may pay 3 life in addition to any other costs as you cast this spell.)
If Phyrexian Scuta was kicked, it enters with two +1/+1 counters on it.

Extirpate

Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
Choose target card in a graveyard other than a basic land card. Search its owner's graveyard, hand, and library for all cards with the same name as that card and exile them. Then that player shuffles.

Hundroog

Cycling {3} ({3}, Discard this card: Draw a card.)

Graxiplon

Graxiplon can't be blocked unless defending player controls three or more creatures that share a creature type.

Forlorn Pseudamma

Intimidate (This creature can't be blocked except by artifact creatures and/or creatures that share a color with it.)
Inspired — Whenever Forlorn Pseudamma becomes untapped, you may pay {2}{B}. If you do, create a 2/2 black Zombie enchantment creature token.

Errant Ephemeron

Flying
Suspend 4—{1}{U} (Rather than cast this card from your hand, you may pay {1}{U} and exile it with four time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost. It has haste.)

Wiitigo

Wiitigo enters with six +1/+1 counters on it.
At the beginning of your upkeep, put a +1/+1 counter on Wiitigo if it has blocked or been blocked since your last upkeep. Otherwise, remove a +1/+1 counter from it.

Juzám Djinn

At the beginning of your upkeep, Juzám Djinn deals 1 damage to you.

Bayou

Ridged Kusite

{1}{B}, {T}, Discard a card: Target creature gets +1/+0 and gains first strike until end of turn.

Qumulox

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Flying

Nyxathid

As Nyxathid enters, choose an opponent.
Nyxathid gets -1/-1 for each card in the chosen player's hand.

Oneirophage

Flying
Whenever you draw a card, put a +1/+1 counter on Oneirophage.

Nevinyrral's Disk

Nevinyrral's Disk enters tapped.
{1}, {T}: Destroy all artifacts, creatures, and enchantments.

Somnophore

Flying
Whenever Somnophore deals damage to a player, tap target creature that player controls. That creature doesn't untap during its controller's untap step for as long as Somnophore remains on the battlefield.

Mischievous Quanar

{3}{U}{U}: Turn Mischievous Quanar face down.
Morph {1}{U}{U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
When Mischievous Quanar is turned face up, copy target instant or sorcery spell. You may choose new targets for that copy.

Island

Zndrsplt, Eye of Wisdom

Partner with Okaun, Eye of Chaos (When this creature enters, target player may put Okaun into their hand from their library, then shuffle.)
At the beginning of combat on your turn, flip a coin until you lose a flip.
Whenever a player wins a coin flip, draw a card.

Unesh, Criosphinx Sovereign

Flying
Sphinx spells you cast cost {2} less to cast.
Whenever Unesh, Criosphinx Sovereign or another Sphinx you control enters, reveal the top four cards of your library. An opponent separates those cards into two piles. Put one pile into your hand and the other into your graveyard.

Saprazzan Skerry

Saprazzan Skerry enters tapped with two depletion counters on it.
{T}, Remove a depletion counter from Saprazzan Skerry: Add {U}{U}. If there are no depletion counters on Saprazzan Skerry, sacrifice it.

Ichthyomorphosis

Enchant creature
Enchanted creature loses all abilities and is a blue Fish with base power and toughness 0/1.

Nacatl Savage

The Mimeoplasm

As The Mimeoplasm enters, you may exile two creature cards from graveyards. If you do, it enters as a copy of one of those cards with a number of additional +1/+1 counters on it equal to the power of the other card.

Ravenous Leucrocota

Vigilance
{6}{G}: Monstrosity 3. (If this creature isn't monstrous, put three +1/+1 counters on it and it becomes monstrous.)

Forest

Triskelavus

Flying
Triskelavus enters with three +1/+1 counters on it.
{1}, Remove a +1/+1 counter from Triskelavus: Create a 1/1 colorless Triskelavite artifact creature token with flying. It has "Sacrifice this creature: This creature deals 1 damage to any target."

Mirozel

Flying
When Mirozel becomes the target of a spell or ability, return Mirozel to its owner's hand.

Xenic Poltergeist

{T}: Until your next upkeep, target noncreature artifact becomes an artifact creature with power and toughness each equal to its mana value.

Crypt of Agadeem

Crypt of Agadeem enters tapped.
{T}: Add {B}.
{2}, {T}: Add {B} for each black creature card in your graveyard.

Whippoorwill

{G}{G}, {T}: Target creature can't be regenerated this turn. Damage that would be dealt to that creature this turn can't be prevented or dealt instead to another permanent or player. When the creature dies this turn, exile the creature.

Ancient Ziggurat

{T}: Add one mana of any color. Spend this mana only to cast a creature spell.

Zoetic Cavern

{T}: Add {C}.
Morph {2} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Scalpelexis

Flying (This creature can't be blocked except by creatures with flying or reach.)
Whenever Scalpelexis deals combat damage to a player, that player exiles the top four cards of their library. If two or more of those cards have the same name, repeat this process.

Lignify

Enchant creature
Enchanted creature is a Treefolk with base power and toughness 0/4 and loses all abilities.

Kurgadon

Whenever you cast a creature spell with mana value 6 or greater, put three +1/+1 counters on Kurgadon.

Groffskithur

Whenever Groffskithur becomes blocked, you may return target card named Groffskithur from your graveyard to your hand.

Citanul Hierophants

Creatures you control have "{T}: Add {G}."

Prowling Serpopard

This spell can't be countered.
Creature spells you control can't be countered.

Yixlid Jailer

Moroii

Flying
At the beginning of your upkeep, you lose 1 life.

Vacuumelt

Replicate {2}{U} (When you cast this spell, copy it for each time you paid its replicate cost. You may choose new targets for the copies.)
Return target creature to its owner's hand.

Quagnoth

Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
Shroud (This creature can't be the target of spells or abilities.)
When a spell or ability an opponent controls causes you to discard Quagnoth, return it to your hand.

Ifh-Bíff Efreet

Flying
{G}: Ifh-Bíff Efreet deals 1 damage to each creature with flying and each player. Any player may activate this ability.

Colfenor's Urn

Whenever a creature with toughness 4 or greater is put into your graveyard from the battlefield, you may exile it.
At the beginning of the end step, if three or more cards have been exiled with Colfenor's Urn, sacrifice it. If you do, return those cards to the battlefield under their owner's control.

Zhalfirin Void

When Zhalfirin Void enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{T}: Add {C}.

Tukatongue Thallid

When Tukatongue Thallid dies, create a 1/1 green Saproling creature token.

Marjhan

Marjhan doesn't untap during your untap step.
{U}{U}, Sacrifice a creature: Untap Marjhan. Activate only during your upkeep.
Marjhan can't attack unless defending player controls an Island.
{U}{U}: Marjhan gets -1/-0 until end of turn and deals 1 damage to target attacking creature without flying.
When you control no Islands, sacrifice Marjhan.

Oubliette

When Oubliette enters, target creature phases out until Oubliette leaves the battlefield. Tap that creature as it phases in this way. (Auras and Equipment phase out with it. While permanents are phased out, they're treated as though they don't exist.)