Terror Tide

Fathomless descent — All creatures get -X/-X until end of turn, where X is the number of permanent cards in your graveyard.

Swashbuckler's Whip

Equipped creature has reach, "{2}, {T}: Tap target artifact or creature," and "{8}, {T}: Discover 10." (Exile cards from the top of your library until you exile a nonland card with mana value 10 or less. Cast it without paying its mana cost or put it into your hand. Put the rest on the bottom in a random order.)
Equip {1}

Huatli's Final Strike

Target creature you control gets +1/+0 until end of turn. It deals damage equal to its power to target creature an opponent controls.

Sentinel of the Nameless City

Vigilance
Whenever this creature enters or attacks, create a Map token. (It's an artifact with "{1}, {T}, Sacrifice this token: Target creature you control explores. Activate only as a sorcery.")

Acolyte of Aclazotz

{T}, Sacrifice another creature or artifact: Each opponent loses 1 life and you gain 1 life.

Swamp

Coati Scavenger

Descend 4 — When this creature enters, if there are four or more permanent cards in your graveyard, return target permanent card from your graveyard to your hand.

Earthshaker Dreadmaw

Trample
When this creature enters, draw a card for each other Dinosaur you control.

Scampering Surveyor

When this creature enters, search your library for a basic land card or Cave card, put it onto the battlefield tapped, then shuffle.

Fanatical Offering

As an additional cost to cast this spell, sacrifice an artifact or creature.
Draw two cards and create a Map token. (It's an artifact with "{1}, {T}, Sacrifice this token: Target creature you control explores. Activate only as a sorcery.")

Canonized in Blood

At the beginning of your end step, if you descended this turn, put a +1/+1 counter on target creature you control. (You descended if a permanent card was put into your graveyard from anywhere.)
{5}{B}{B}, Sacrifice this enchantment: Create a 4/3 white and black Vampire Demon creature token with flying.

Deathcap Marionette

Deathtouch
When this creature enters, you may mill two cards. (You may put the top two cards of your library into your graveyard.)

Deep Goblin Skulltaker

Menace
At the beginning of your end step, if you descended this turn, put a +1/+1 counter on this creature. (You descended if a permanent card was put into your graveyard from anywhere.)

Malamet Veteran

Trample
Descend 4 — Whenever this creature attacks, if there are four or more permanent cards in your graveyard, put a +1/+1 counter on target creature.

Primordial Gnawer

When this creature dies, discover 3. (Exile cards from the top of your library until you exile a nonland card with mana value 3 or less. Cast it without paying its mana cost or put it into your hand. Put the rest on the bottom in a random order.)

Disturbed Slumber

Until end of turn, target land you control becomes a 4/4 Dinosaur creature with reach and haste. It's still a land. It must be blocked this turn if able.

Hidden Nursery

This land enters tapped.
{T}: Add {G}.
{4}{G}, {T}, Sacrifice this land: Discover 4. Activate only as a sorcery. (Exile cards from the top of your library until you exile a nonland card with mana value 4 or less. Cast it without paying its mana cost or put it into your hand. Put the rest on the bottom in a random order.)

Shadows' Lair

(Transforms from Grasping Shadows.)
{T}: Add {B}.
{B}, {T}, Remove a dread counter from this land: You draw a card and you lose 1 life.

Grasping Shadows

Whenever a creature you control attacks alone, it gains deathtouch and lifelink until end of turn. Put a dread counter on this enchantment. Then if there are three or more dread counters on it, transform it.

Grasping Shadows // Shadows' Lair

Rampaging Spiketail

When this creature enters, target creature you control gets +2/+0 and gains indestructible until end of turn.
Swampcycling {2} ({2}, Discard this card: Search your library for a Swamp card, reveal it, put it into your hand, then shuffle.)

Broodrage Mycoid

At the beginning of your end step, if you descended this turn, create a 1/1 black Fungus creature token with "This token can't block." (You descended if a permanent card was put into your graveyard from anywhere.)

Consuming Sepulcher

At the beginning of your upkeep, each opponent loses 1 life and you gain 1 life.

Tithing Blade

When this artifact enters, each opponent sacrifices a creature of their choice.
Craft with creature {4}{B} ({4}{B}, Exile this artifact, Exile a creature you control or a creature card from your graveyard: Return this card transformed under its owner's control. Craft only as a sorcery.)

Tithing Blade // Consuming Sepulcher

Forest

Cavern Stomper

When this creature enters, scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)
{3}{G}: This creature can't be blocked by creatures with power 2 or less this turn.

Promising Vein

{T}: Add {C}.
{1}, {T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Armored Kincaller

When this creature enters, you may reveal a Dinosaur card from your hand. If you do or if you control another Dinosaur, you gain 3 life.

Jadelight Spelunker

When this creature enters, it explores X times. (To have it explore, reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on that creature, then put the card back or put it into your graveyard.)

Captivating Cave

{T}: Add {C}.
{1}, {T}: Add one mana of any color.
{4}, {T}, Sacrifice this land: Put two +1/+1 counters on target creature. Activate only as a sorcery.

Hidden Necropolis

This land enters tapped.
{T}: Add {B}.
{4}{B}, {T}, Sacrifice this land: Discover 4. Activate only as a sorcery. (Exile cards from the top of your library until you exile a nonland card with mana value 4 or less. Cast it without paying its mana cost or put it into your hand. Put the rest on the bottom in a random order.)