Forest

Heap Gate

{T}: Add {C}.
{1}, {T}: Add one mana of any color.
{1}, {T}, Tap an untapped Gate you control: Create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Nefarious Imp

Flying
Whenever one or more permanents you control leave the battlefield, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Far Traveler

Commander creatures you own have "At the beginning of your end step, exile up to one target tapped creature you control, then return it to the battlefield under its owner's control."

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.)

Jaheira's Respite

Search your library for up to X basic land cards, where X is the number of creatures attacking you, put those cards onto the battlefield tapped, then shuffle.
Prevent all combat damage that would be dealt this turn.

Plains

Ascend from Avernus

Return all creature and planeswalker cards with mana value X or less from your graveyard to the battlefield. Exile Ascend from Avernus.

Silvanus's Invoker

Conjure Elemental — {8}: Untap target land you control. It becomes an 8/8 Elemental creature with trample and haste until end of turn. It's still a land.

Myconid Spore Tender

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

Swamp

Marble Diamond

Marble Diamond enters tapped.
{T}: Add {W}.

Cloudkill

All creatures get -X/-X until end of turn, where X is the greatest mana value of a commander you own on the battlefield or in the command zone.

Nature's Lore

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

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.

Underdark Explorer

Menace (This creature can't be blocked except by two or more creatures.)
When Underdark Explorer enters, you take the initiative.

Minimus Containment

Enchant nonland permanent
Enchanted permanent is a Treasure artifact with "{T}, Sacrifice this artifact: Add one mana of any color," and it loses all other abilities. (If it was a creature, it's no longer a creature.)

Passageway Seer

Lifelink
When Passageway Seer enters, you take the initiative.
At the beginning of your end step, if you have the initiative, put a +1/+1 counter on Passageway Seer.

Avenging Hunter

Trample
When Avenging Hunter enters, you take the initiative.

Zoological Study

Mill five cards, then return a creature card milled this way to your hand. (Then exile this card. You may cast the artifact later from exile.)

Monster Manual

{1}{G}, {T}: You may put a creature card from your hand onto the battlefield.

Monster Manual // Zoological Study

Sarevok, Deathbringer

At the beginning of each player's end step, if no permanents left the battlefield this turn, that player loses X life, where X is Sarevok's power.
Choose a Background (You can have a Background as a second commander.)

Arms of Hadar

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

Charcoal Diamond

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

Abdel Adrian, Gorion's Ward

When Abdel Adrian, Gorion's Ward enters, exile any number of other nonland permanents you control until Abdel Adrian leaves the battlefield. Create a 1/1 white Soldier creature token for each permanent exiled this way.
Choose a Background (You can have a Background as a second commander.)

Intellect Devourer

Devour Intellect — When Intellect Devourer enters, each opponent exiles a card from their hand until Intellect Devourer leaves the battlefield.
Body Thief — You may play lands and cast spells from among cards exiled with Intellect Devourer. If you cast a spell this way, you may spend mana as though it were mana of any color to cast it.

Dawnbringer Cleric

When Dawnbringer Cleric enters, choose one —
• Cure Wounds — You gain 2 life.
• Dispel Magic — Destroy target enchantment.
• Gentle Repose — Exile target card from a graveyard.

Command Tower

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

Sivriss, Nightmare Speaker

{T}, Sacrifice another creature or an artifact: For each opponent, you mill a card, then return that card from your graveyard to your hand unless that player pays 3 life. (To mill a card, put the top card of your library into your graveyard.)
Choose a Background (You can have a Background as a second commander.)

Roving Harper

Mold Folk

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

Your Temple Is Under Attack

Choose one —
• Pray for Protection — Creatures you control gain indestructible until end of turn.
• Strike a Deal — You and target opponent each draw two cards.

Myrkul's Edict

Roll a d20.
1—9 | Choose an opponent. That player sacrifices a creature of their choice.
10—19 | Each opponent sacrifices a creature of their choice.
20 | Each opponent sacrifices a creature with the greatest power among creatures that player controls.

Manor Gate

Manor Gate enters tapped.
As Manor Gate enters, choose a color other than green.
{T}: Add {G} or one mana of the chosen color.

Myrkul, Lord of Bones

As long as your life total is less than or equal to half your starting life total, Myrkul, Lord of Bones has indestructible.
Whenever another nontoken creature you control dies, you may exile it. If you do, create a token that's a copy of that card, except it's an enchantment and loses all other card types.

Lantern of Revealing

{T}: Add one mana of any color.
{4}, {T}: Look at the top card of your library. If it's a land card, you may put it onto the battlefield tapped. If you don't put the card onto the battlefield, you may put it on the bottom of your library.

Burnished Hart

{3}, Sacrifice this creature: Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.