Erkenbrand, Lord of Westfold

Whenever Erkenbrand or another Human you control enters, creatures you control get +1/+0 until end of turn.

Rivendell

Rivendell enters tapped unless you control a legendary creature.
{T}: Add {U}.
{1}{U}, {T}: Scry 2. Activate only if you control a legendary creature.

Mirror of Galadriel

{5}, {T}: Scry 1, then draw a card. This ability costs {1} less to activate for each legendary creature you control.

Éowyn, Lady of Rohan

At the beginning of combat on your turn, target creature gains your choice of first strike or vigilance until end of turn. If that creature is equipped, it gains first strike and vigilance until end of turn instead.
Equip abilities you activate cost {1} less to activate.

Great Hall of the Citadel

{T}: Add {C}.
{1}, {T}: Add two mana in any combination of colors. Spend this mana only to cast legendary spells.

Soothing of Sméagol

Return target nontoken creature to its owner's hand. The Ring tempts you.

Sam's Desperate Rescue

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

Forest

Bombadil's Song

Target creature you control gets +1/+1 and gains hexproof until end of turn. The Ring tempts you. (A creature with hexproof can't be the target of spells or abilities your opponents control.)

Bag End Porter

Whenever this creature attacks, it gets +X/+X until end of turn, where X is the number of legendary creatures you control.

Shire Terrace

{T}: Add {C}.
{1}, {T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Ioreth of the Healing House

{T}: Untap another target permanent.
{T}: Untap two other target legendary creatures.

Elrond, Lord of Rivendell

Whenever Elrond or another creature you control enters, scry 1. If this is the second time this ability has resolved this turn, the Ring tempts you.

Théoden, King of Rohan

Whenever Théoden or another Human you control enters, target creature gains double strike until end of turn.

Quarrel's End

As an additional cost to cast this spell, discard a card.
Draw two cards and create a 1/1 white Human Soldier creature token.

Mirkwood Spider

Deathtouch
Whenever this creature attacks, target legendary creature you control gains deathtouch until end of turn.

Saruman the White

Ward {2}
Whenever you cast your second spell each turn, 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.)

Lembas

When this artifact enters, scry 1, then draw a card.
{2}, {T}, Sacrifice this artifact: You gain 3 life.
When this artifact is put into a graveyard from the battlefield, its owner shuffles it into their library.

Banish from Edoras

This spell costs {2} less to cast if it targets a tapped creature.
Exile target creature.

Gimli's Fury

Target creature gets +3/+2 until end of turn. If it's legendary, it also gains trample until end of turn.

Swamp

Slip On the Ring

Exile target creature you own, then return it to the battlefield under your control. The Ring tempts you.

Glóin, Dwarf Emissary

Whenever you cast a historic spell, create a Treasure token. This ability triggers only once each turn. (Artifacts, legendaries, and Sagas are historic.)
{T}, Sacrifice a Treasure: Goad target creature. (Until your next turn, that creature attacks each combat if able and attacks a player other than you if able.)

Soldier of the Grey Host

Flash
Flying
When this creature enters, target creature gets +2/+0 until end of turn.

Plains

Mountain

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.

Lórien Revealed

Draw three cards.
Islandcycling {1} ({1}, Discard this card: Search your library for an Island card, reveal it, put it into your hand, then shuffle.)

Island

Swarming of Moria

Create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: 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.)

Butterbur, Bree Innkeeper

At the beginning of your end step, if you don't control a Food, create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this token: You gain 3 life.")

Delighted Halfling

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a legendary spell, and that spell can't be countered.

The Shire

The Shire enters tapped unless you control a legendary creature.
{T}: Add {G}.
{1}{G}, {T}, Tap an untapped creature you control: Create a Food token.

Inherited Envelope

When this artifact enters, the Ring tempts you.
{T}: Add one mana of any color.

Sting, the Glinting Dagger

Equipped creature gets +1/+1 and has haste.
At the beginning of each combat, untap equipped creature.
Equipped creature has first strike as long as it's blocking or blocked by a Goblin or Orc.
Equip {2}

Lash of the Balrog

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

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.