Dog Umbra

Flash
Enchant creature
As long as another player controls enchanted creature, it can't attack or block. Otherwise, this Aura has umbra armor. (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Thraben Inspector

When this creature enters, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Argivian Phalanx

Affinity for creatures (This spell costs {1} less to cast for each creature you control.)
Vigilance (Attacking doesn't cause this creature to tap.)

Plains

Salt Road Packbeast

This spell costs {1} less to cast for each creature you control.
When this creature enters, draw a card.

Luminous Phantom

Flying
Whenever another creature you control leaves the battlefield, you gain 1 life.
If Luminous Phantom would be put into a graveyard from anywhere, exile it instead.

Lunarch Veteran

Whenever another creature you control enters, you gain 1 life.
Disturb {1}{W} (You may cast this card from your graveyard transformed for its disturb cost.)

Lunarch Veteran // Luminous Phantom

Sacred Cat

Lifelink
Embalm {W} ({W}, Exile this card from your graveyard: Create a token that's a copy of it, except it's a white Zombie Cat with no mana cost. Embalm only as a sorcery.)

Inspiring Overseer

Flying
When this creature enters, you gain 1 life and draw a card.

Raffine's Informant

When this creature enters, it connives. (Draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on this creature.)

Thraben Charm

Choose one —
• Thraben Charm deals damage equal to twice the number of creatures you control to target creature.
• Destroy target enchantment.
• Exile any number of target players' graveyards.

Search Party Captain

This spell costs {1} less to cast for each creature you attacked with this turn.
When this creature enters, draw a card.

Helpful Hunter

Spirited Companion

Warren Elder

{3}{W}: Creatures you control get +1/+1 until end of turn.

Signaling Roar

Create a 2/2 white Soldier creature token. (Then shuffle this card into its owner's library.)

Riling Dawnbreaker

Flying, vigilance
At the beginning of combat on your turn, another target creature you control gets +1/+0 until end of turn.

Riling Dawnbreaker // Signaling Roar

Secluded Steppe

This land enters tapped.
{T}: Add {W}.
Cycling {W} ({W}, Discard this card: Draw a card.)

Battle Screech

Create two 1/1 white Bird creature tokens with flying.
Flashback—Tap three untapped white creatures you control. (You may cast this card from your graveyard for its flashback cost. Then exile it.)