Plains

Nomad Outpost

This land enters tapped.
{T}: Add {R}, {W}, or {B}.

Salt Road Packbeast

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

Mardu Devotee

When this creature 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.)
{1}: Add {R}, {W}, or {B}. Activate only once each turn.

Desperate Measures

Target creature gets +1/-1 until end of turn. When it dies under your control this turn, draw two cards.

War Effort

Creatures you control get +1/+0.
Whenever you attack, create a 1/1 red Warrior creature token that's tapped and attacking. Sacrifice it at the beginning of the next end step.

Bone-Cairn Butcher

Mobilize 2 (Whenever this creature attacks, create two tapped and attacking 1/1 red Warrior creature tokens. Sacrifice them at the beginning of the next end step.)
Attacking tokens you control have deathtouch.

Mountain

Shock Brigade

Menace (This creature can't be blocked except by two or more creatures.)
Mobilize 1 (Whenever this creature attacks, create a tapped and attacking 1/1 red Warrior creature token. Sacrifice it at the beginning of the next end step.)

Unsparing Boltcaster

When this creature enters, it deals 5 damage to target creature an opponent controls that was dealt damage this turn.

Bloodfell Caves

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {B} or {R}.

Bearer of Glory

During your turn, this creature has first strike.
{4}{W}: Creatures you control get +1/+1 until end of turn.

Starry-Eyed Skyrider

Flying
Whenever this creature attacks, another target creature you control gains flying until end of turn.
Attacking tokens you control have flying.

Dalkovan Packbeasts

Vigilance
Mobilize 3 (Whenever this creature attacks, create three tapped and attacking 1/1 red Warrior creature tokens. Sacrifice them at the beginning of the next end step.)

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

Static Snare

Flash
This spell costs {1} less to cast for each attacking creature.
When this enchantment enters, exile target artifact or creature an opponent controls until this enchantment leaves the battlefield.

Mardu Monument

When this artifact enters, search your library for a basic Mountain, Plains, or Swamp card, reveal it, put it into your hand, then shuffle.
{2}{R}{W}{B}, {T}, Sacrifice this artifact: Create three 1/1 red Warrior creature tokens. They gain menace and haste until end of turn. Activate only as a sorcery. (A creature with menace can't be blocked except by two or more creatures.)

Nightblade Brigade

Deathtouch
Mobilize 1 (Whenever this creature attacks, create a tapped and attacking 1/1 red Warrior creature token. Sacrifice it at the beginning of the next end step.)
When this creature enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Dragonback Lancer

Flying
Mobilize 1 (Whenever this creature attacks, create a tapped and attacking 1/1 red Warrior creature token. Sacrifice it at the beginning of the next end step.)

Worthy Cost

As an additional cost to cast this spell, sacrifice a creature.
Exile target creature or planeswalker.

Shocking Sharpshooter

Reach
Whenever another creature you control enters, this creature deals 1 damage to target opponent.

Reigning Victor

Mobilize 1 (Whenever this creature attacks, create a tapped and attacking 1/1 red Warrior creature token. Sacrifice it at the beginning of the next end step.)
When this creature enters, target creature gets +1/+0 and gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)