Tyvar, Jubilant Brawler

You may activate abilities of creatures you control as though those creatures had haste.
+1: Untap up to one target creature.
−2: Mill three cards, then you may return a creature card with mana value 2 or less from your graveyard to the battlefield.

Grist, the Hunger Tide

As long as Grist isn't on the battlefield, it's a 1/1 Insect creature in addition to its other types.
+1: Create a 1/1 black and green Insect creature token, then mill a card. If an Insect card was milled this way, put a loyalty counter on Grist and repeat this process.
−2: You may sacrifice a creature. When you do, destroy target creature or planeswalker.
−5: Each opponent loses life equal to the number of creature cards in your graveyard.

The Core

(Transforms from Matzalantli.)
Fathomless descent — {T}: Add X mana of any one color, where X is the number of permanent cards in your graveyard.

Matzalantli, the Great Door

{T}: Draw a card, then discard a card.
{4}, {T}: Transform Matzalantli. Activate only if there are four or more permanent types among cards in your graveyard. (Artifact, battle, creature, enchantment, land, and planeswalker are permanent types.)

Matzalantli, the Great Door // The Core

Seal of Primordium

Sacrifice this enchantment: Destroy target artifact or enchantment.

Haywire Mite

When this creature dies, you gain 2 life.
{G}, Sacrifice this creature: Exile target noncreature artifact or noncreature enchantment.

Faithless Looting

Draw two cards, then discard two cards.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Twitching Doll

{T}: Add one mana of any color. Put a nest counter on this creature.
{T}, Sacrifice this creature: Create a 2/2 green Spider creature token with reach for each counter on this creature. Activate only as a sorcery.

Tarmogoyf Nest

Enchant land
Enchanted land has "{1}{G}, {T}: Create a Tarmogoyf token." (It's a {1}{G} Lhurgoyf creature with "Tarmogoyf's power is equal to the number of card types among cards in all graveyards and its toughness is equal to that number plus 1.")

Terror Tide

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

Dragon's Rage Channeler

Whenever you cast a noncreature spell, surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)
Delirium — As long as there are four or more card types among cards in your graveyard, this creature gets +2/+2, has flying, and attacks each combat if able.

Malevolent Rumble

Reveal the top four cards of your library. You may put a permanent card from among them into your hand. Put the rest into your graveyard. Create a 0/1 colorless Eldrazi Spawn creature token with "Sacrifice this token: Add {C}."

Korvold, Fae-Cursed King

Flying
Whenever Korvold enters or attacks, sacrifice another permanent.
Whenever you sacrifice a permanent, put a +1/+1 counter on Korvold and draw a card.

Demonic Counsel

Search your library for a Demon card, reveal it, put it into your hand, then shuffle.
Delirium — If there are four or more card types among cards in your graveyard, instead search your library for any card, put it into your hand, then shuffle.

Korvold, Gleeful Glutton

This spell costs {1} less to cast for each card type among permanents you've sacrificed this turn.
Flying, trample, haste
Whenever Korvold deals combat damage to a player, put X +1/+1 counters on Korvold and draw X cards, where X is the number of permanent types among cards in your graveyard.

Blood Pet

Sakura-Tribe Elder

Sacrifice this creature: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Reckless Barbarian

Lizard Blades

Double strike
Equipped creature has double strike.
Reconfigure {2} ({2}: Attach to target creature you control; or unattach from a creature. Reconfigure only as a sorcery. While attached, this isn't a creature.)

Deluge of Doom

All creatures get -X/-X until end of turn, where X is the number of card types among cards in your graveyard.

Baba Lysaga, Night Witch

{T}, Sacrifice up to three permanents: If there were three or more card types among the sacrificed permanents, each opponent loses 3 life, you gain 3 life, and you draw three cards.

Minsc & Boo, Timeless Heroes

When Minsc & Boo enters and at the beginning of your upkeep, you may create Boo, a legendary 1/1 red Hamster creature token with trample and haste.
+1: Put three +1/+1 counters on up to one target creature with trample or haste.
−2: Sacrifice a creature. When you do, Minsc & Boo deals X damage to any target, where X is that creature's power. If the sacrificed creature was a Hamster, draw X cards.
Minsc & Boo, Timeless Heroes can be your commander.

Fear of Missing Out

When this creature enters, discard a card, then draw a card.
Delirium — Whenever this creature attacks for the first time each turn, if there are four or more card types among cards in your graveyard, untap target creature. After this phase, there is an additional combat phase.

Goldhound

First strike
Menace (This creature can't be blocked except by two or more creatures.)
{T}, Sacrifice this creature: Add one mana of any color.

Diamond Lion

{T}, Discard your hand, Sacrifice this creature: Add three mana of any one color. Activate only as an instant.

Evolving Wilds

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

Wild Cantor

({R/G} can be paid with either {R} or {G}.)
Sacrifice this creature: Add one mana of any color.

Peer Past the Veil

Discard your hand. Then draw X cards, where X is the number of card types among cards in your graveyard.

Rottenmouth Viper

As an additional cost to cast this spell, you may sacrifice any number of nonland permanents. This spell costs {1} less to cast for each permanent sacrificed this way.
Whenever this creature enters or attacks, put a blight counter on it. Then for each blight counter on it, each opponent loses 4 life unless that player sacrifices a nonland permanent of their choice or discards a card.

Sol Ring

Ignoble Hierarch

Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)
{T}: Add {B}, {R}, or {G}.

Traverse the Ulvenwald

Search your library for a basic land card, reveal it, put it into your hand, then shuffle.
Delirium — If there are four or more card types among cards in your graveyard, instead search your library for a creature or land card, reveal it, put it into your hand, then shuffle.

Ash Barrens

{T}: Add {C}.
Basic landcycling {1} ({1}, Discard this card: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.)

Omnivorous Flytrap

Delirium — Whenever this creature enters or attacks, if there are four or more card types among cards in your graveyard, distribute two +1/+1 counters among one or two target creatures. Then if there are six or more card types among cards in your graveyard, double the number of +1/+1 counters on those creatures.

Ursine Monstrosity

Trample
At the beginning of combat on your turn, mill a card and choose an opponent at random. This creature attacks that player this combat if able. Until end of turn, this creature gains indestructible and gets +1/+1 for each card type among cards in your graveyard.

Disa the Restless

Whenever a Lhurgoyf permanent card is put into your graveyard from anywhere other than the battlefield, put it onto the battlefield.
Whenever one or more creatures you control deal combat damage to a player, create a Tarmogoyf token.

Demolisher Spawn

Trample, haste
Delirium — Whenever this creature attacks, if there are four or more card types among cards in your graveyard, other attacking creatures get +4/+4 until end of turn.

Gilded Goose

Flying
When this creature enters, create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this token: You gain 3 life.")
{1}{G}, {T}: Create a Food token.
{T}, Sacrifice a Food: Add one mana of any color.

Bloodstained Mire

{T}, Pay 1 life, Sacrifice this land: Search your library for a Swamp or Mountain card, put it onto the battlefield, then shuffle.

Seal of Doom

Sacrifice this enchantment: Destroy target nonblack creature. It can't be regenerated.

Terramorphic Expanse

Cindervines

Whenever an opponent casts a noncreature spell, this enchantment deals 1 damage to that player.
{1}, Sacrifice this enchantment: Destroy target artifact or enchantment. This enchantment deals 2 damage to that permanent's controller.

Twisted Landscape

{T}: Add {C}.
{T}, Sacrifice this land: Search your library for a basic Swamp, Mountain, or Forest card, put it onto the battlefield tapped, then shuffle.
Cycling {B}{R}{G} ({B}{R}{G}, Discard this card: Draw a card.)