Mountain

Explosive Crystal

Explosive Crystal deals 4 damage divided as you choose among any number of targets. (Then exile this card. You may cast the creature later from exile.)

Amethyst Dragon

Amethyst Dragon // Explosive Crystal

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

Bathe in Gold

Create a Treasure token. (Then exile this card. You may cast the creature later from exile.)

Young Red Dragon

Young Red Dragon // Bathe in Gold

Pack Attack

Attacking creatures get +X/+0 until end of turn, where X is the number of players being attacked.
Draw a card.

Stirring Bard

Defender
When Stirring Bard enters, you take the initiative.
Mantle of Inspiration — {T}: Target creature gains menace and haste until end of turn.

Poison the Blade

Target creature gains deathtouch until end of turn.
Draw a card.

Evolving Wilds

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

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.

Insufferable Balladeer

Vicious Mockery — When Insufferable Balladeer enters, target creature an opponent controls can't block this turn. Goad it. (Until your next turn, that creature attacks each combat if able and attacks a player other than you if able.)

Undercellar Myconid

When Undercellar Myconid enters or dies, create a 1/1 green Saproling creature token.
{T}: Add one mana of any color.

Inspired Tinkering

Exile the top three cards of your library. Until the end of your next turn, you may play those cards.
Create three Treasure tokens. (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

Forest

Lurking Green Dragon

Flying
Lurking Green Dragon can't attack unless defending player controls a creature with flying.

Hoarding Ogre

Whenever Hoarding Ogre attacks, roll a d20.
1—9 | Create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
10—19 | Create two Treasure tokens.
20 | Create three Treasure tokens.

Ganax, Astral Hunter

Flying
Whenever Ganax, Astral Hunter or another Dragon you control enters, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
Choose a Background (You can have a Background as a second commander.)

Moss Diamond

Moss Diamond enters tapped.
{T}: Add {G}.

Fire Diamond

Fire Diamond enters tapped.
{T}: Add {R}.

Forktail Sweep

Forktail Sweep deals 1 damage to each creature you don't control. (Then exile this card. You may cast the creature later from exile.)

Fang Dragon

Fang Dragon // Forktail Sweep

Druid of the Emerald Grove

When Druid of the Emerald Grove enters, search your library for up to two basic land cards and reveal them, then roll a d20.
9 or less | Put those cards into your hand, then shuffle.
10—19 | Put one of those cards onto the battlefield tapped and the other into your hand, then shuffle.
20+ | Put those cards onto the battlefield tapped, then shuffle.

Coronation of Chaos

Up to three target creatures can't block this turn. Goad them. (Until your next turn, those creatures attack each combat if able and attack a player other than you if able.)

Earthquake Dragon

This spell costs {X} less to cast, where X is the total mana value of Dragons you control.
Flying, trample
{2}{G}, Sacrifice a land: Return Earthquake Dragon from your graveyard to your hand.

Cliffgate

Cliffgate enters tapped.
As Cliffgate enters, choose a color other than red.
{T}: Add {R} or one mana of the chosen color.

Minsc & Boo, Timeless Heroes

When Minsc & Boo, Timeless Heroes 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, Timeless Heroes 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.

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.

Patron of the Arts

When Patron of the Arts enters or dies, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Tiamat's Fanatics

Haste
Myriad (Whenever this creature attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)

Earth Tremor

Earth Tremor deals damage to target creature or planeswalker equal to the number of lands you control.

Thunderwave

Roll a d20.
1—9 | Thunderwave deals 3 damage to each creature.
10—19 | You may choose a creature. Thunderwave deals 3 damage to each creature not chosen this way.
20 | Thunderwave deals 6 damage to each creature your opponents control.

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.)