Swarming of Moria

Create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
Amass Orcs 2. (Put two +1/+1 counters on an Army you control. It's also an Orc. If you don't control an Army, create a 0/0 black Orc Army creature token first.)

Haradrim Spearmaster

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

Warbeast of Gorgoroth

Whenever Warbeast of Gorgoroth or another creature you control with power 4 or greater dies, amass Orcs 2. (Put two +1/+1 counters on an Army you control. It's also an Orc. If you don't control an Army, create a 0/0 black Orc Army creature token first.)

Fiery Inscription

When Fiery Inscription enters, the Ring tempts you.
Whenever you cast an instant or sorcery spell, Fiery Inscription deals 2 damage to each opponent.

Lash of the Balrog

As an additional cost to cast this spell, sacrifice a creature or pay {4}.
Destroy target creature.

Sam's Desperate Rescue

Return target creature card from your graveyard to your hand. The Ring tempts you.

Ranger's Firebrand

Ranger's Firebrand deals 2 damage to any target. The Ring tempts you.

Rush the Room

Target creature gets +1/+0 and gains first strike until end of turn. If it's a Goblin or Orc, it also gains haste until end of turn.

Oliphaunt

Trample
Whenever Oliphaunt attacks, another target creature you control gets +2/+0 and gains trample until end of turn.
Mountaincycling {1} ({1}, Discard this card: Search your library for a Mountain card, reveal it, put it into your hand, then shuffle.)

Troll of Khazad-dûm

Troll of Khazad-dûm can't be blocked except by three or more creatures.
Swampcycling {1} ({1}, Discard this card: Search your library for a Swamp card, reveal it, put it into your hand, then shuffle.)

The Grey Havens

When The Grey Havens enters, scry 1.
{T}: Add {C}.
{T}: Add one mana of any color among legendary creature cards in your graveyard.

Stone of Erech

If a creature an opponent controls would die, exile it instead.
{2}, {T}, Sacrifice Stone of Erech: Exile target player's graveyard. Draw a card.

Erebor Flamesmith

Whenever you cast an instant or sorcery spell, Erebor Flamesmith deals 1 damage to each opponent.

Dunland Crebain

Flying
When Dunland Crebain enters, amass Orcs 2. (Put two +1/+1 counters on an Army you control. It's also an Orc. If you don't control an Army, create a 0/0 black Orc Army creature token first.)

Mount Doom

{T}, Pay 1 life: Add {B} or {R}.
{1}{B}{R}, {T}: Mount Doom deals 1 damage to each opponent.
{5}{B}{R}, {T}, Sacrifice Mount Doom and a legendary artifact: Choose up to two creatures, then destroy the rest. Activate only as a sorcery.

Uruk-hai Berserker

When Uruk-hai Berserker enters, the Ring tempts you.

Fire of Orthanc

Destroy target artifact or land. Creatures without flying can't block this turn.

Haunt of the Dead Marshes

When Haunt of the Dead Marshes enters, scry 1.
{2}{B}: Return Haunt of the Dead Marshes from your graveyard to the battlefield tapped. Activate only if you control a legendary creature.

Swamp

Rohirrim Lancer

Menace (This creature can't be blocked except by two or more creatures.)
When Rohirrim Lancer dies, the Ring tempts you.

Mountain

Gothmog, Morgul Lieutenant

When Gothmog, Morgul Lieutenant enters, amass Orcs 1. (Put a +1/+1 counter on an Army you control. It's also an Orc. If you don't control an Army, create a 0/0 black Orc Army creature token first.)
Creature tokens you control have deathtouch.

Fear, Fire, Foes!

Damage can't be prevented this turn. Fear, Fire, Foes! deals X damage to target creature and 1 damage to each other creature with the same controller.