Arms of Hadar

Creatures target player controls get -2/-2 until end of turn.

Entropic Cloud

Creatures you control gain deathtouch until end of turn. (Then exile this card. You may cast the creature later from exile.)

Topaz Dragon

Topaz Dragon // Entropic Cloud

Marut

Trample
When Marut enters, if mana from a Treasure was spent to cast it, create a Treasure token for each mana from a Treasure spent to cast it. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Forest

Web Shot

Destroy target creature with flying. (Then exile this card. You may cast the creature later from exile.)

Ettercap

Ettercap // Web Shot

Universal Solvent

{7}, {T}, Sacrifice Universal Solvent: Destroy target permanent.

Marching Duodrone

Whenever Marching Duodrone attacks, each player creates a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Ghastly Death Tyrant

When Ghastly Death Tyrant enters, choose one —
• Disintegration Ray — Destroy target enchantment an opponent controls. You lose life equal to its mana value.
• Death Ray — Creatures you control gain deathtouch until end of turn.

Dig Deep

Choose target creature. Mill four cards, then put a +1/+1 counter on that creature for each creature card milled this way.

Colossal Badger

When Colossal Badger enters, you gain 3 life.

Colossal Badger // Dig Deep

Swamp

Mold Folk

Lifelink
Mold Harvest — {1}, Sacrifice another creature or an artifact: Put a +1/+1 counter on Mold Folk.

Owlbear Shepherd

At the beginning of your end step, if creatures you control have total power 8 or greater, draw a card.

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.

Ambitious Dragonborn

Ambitious Dragonborn enters with X +1/+1 counters on it, where X is the greatest power among creatures you control and creature cards in your graveyard.

Stonespeaker Crystal

{T}: Add {C}{C}.
{2}, {T}, Sacrifice Stonespeaker Crystal: Exile any number of target players' graveyards. Draw a card.

Predatory Impetus

Enchant creature
Enchanted creature gets +3/+3, must be blocked if able, and is goaded. (It attacks each combat if able and attacks a player other than you if able.)

Atrocious Experiment

Target player mills two cards, draws two cards, and loses 2 life. (To mill a card, a player puts the top card of their library into their graveyard.)

Dungeoneer's Pack

Dungeoneer's Pack enters tapped.
{2}, {T}, Sacrifice Dungeoneer's Pack: You take the initiative, gain 3 life, draw a card, and create a Treasure token. Activate only as a sorcery. (A Treasure token is an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Arcane Encyclopedia

Armor of Shadows

Until end of turn, target creature gets +1/+0 and gains indestructible. (Damage and effects that say "destroy" don't destroy it.)

Deadly Dispute

As an additional cost to cast this spell, sacrifice an artifact or creature.
Draw two cards and create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Command Tower

{T}: Add one mana of any color in your commander's color identity.

Agent of the Iron Throne

Commander creatures you own have "Whenever an artifact or creature you control is put into a graveyard from the battlefield, each opponent loses 1 life."

Halsin, Emerald Archdruid

{1}: Until end of turn, target token you control becomes a green Bear creature with base power and toughness 4/4 in addition to its other colors and types.
Choose a Background (You can have a Background as a second commander.)

Summon Undead

You may mill three cards. Then return a creature card from your graveyard to the battlefield. (To mill a card, put the top card of your library into your graveyard.)

Nature's Lore

Search your library for a Forest card, put that card onto the battlefield, then shuffle.

Call to the Void

Each player secretly chooses a creature they control and a creature they don't control. Then those choices are revealed. Destroy each creature chosen this way.

Charcoal Diamond

Charcoal Diamond enters tapped.
{T}: Add {B}.

Decanter of Endless Water

You have no maximum hand size.
{T}: Add one mana of any color.

Giant Ankheg

Trample
Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
Other creatures you control have trample and ward {2}.

Ancient Bronze Dragon

Flying
Whenever Ancient Bronze Dragon deals combat damage to a player, roll a d20. When you do, put X +1/+1 counters on each of up to two target creatures, where X is the result.

Geode Golem

Trample
Whenever Geode Golem deals combat damage to a player, you may cast your commander from the command zone without paying its mana cost. (You still pay any additional costs.)

Chain Devil

Animate Chains — When Chain Devil enters, each player sacrifices a nontoken creature of their choice.

Bronze Walrus

When Bronze Walrus 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.)
{T}: Add one mana of any color.

Cloak of the Bat

Equipped creature has flying and haste.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Prized Statue

When Prized Statue enters or is put into a graveyard from the battlefield, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Zhentarim Bandit

Whenever Zhentarim Bandit attacks, you may pay 1 life. If you do, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Myconid Spore Tender

Infesting Spores — When Myconid Spore Tender enters, destroy up to one target artifact or enchantment.