Plains

Hobbit's Sting

Hobbit's Sting deals X damage to target creature, where X is the number of creatures you control plus the number of Foods you control.

Gríma Wormtongue

Your opponents can't gain life.
{T}, Sacrifice another creature: Target player loses 1 life. If the sacrificed creature was legendary, amass Orcs 2.

Cirith Ungol Patrol

{1}, {T}, Sacrifice another creature: Draw a card, then create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this token: You gain 3 life.")

Sam's Desperate Rescue

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

Morgul-Knife Wound

Enchant creature
Enchanted creature gets -3/-0 and has "At the beginning of your upkeep, exile this creature unless you pay 2 life."

Shadow Summoning

Create two tapped 1/1 white Spirit creature tokens with flying.

Gothmog, Morgul Lieutenant

When Gothmog 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.

Swamp

Uruk-hai Berserker

When this creature enters, the Ring tempts you.

Tale of Tinúviel

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Target creature you control gains indestructible for as long as you control this Saga.
II — Return target creature card from your graveyard to the battlefield.
III — Up to two target creatures you control each gain lifelink until end of turn.

Eagles of the North

Flying
When this creature enters, creatures you control get +1/+0 and gain first strike until end of turn.
Plainscycling {1} ({1}, Discard this card: Search your library for a Plains card, reveal it, put it into your hand, then shuffle.)

Samwise the Stouthearted

Flash
When Samwise enters, choose up to one target permanent card in your graveyard that was put there from the battlefield this turn. Return it to your hand. Then the Ring tempts you.

Slip On the Ring

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

Lobelia Sackville-Baggins

Flash
Menace
When Lobelia enters, exile target creature card from an opponent's graveyard that was put there from the battlefield this turn, then create X Treasure tokens, where X is the exiled card's power.

Now for Wrath, Now for Ruin!

Put a +1/+1 counter on each creature you control. They gain vigilance until end of turn. The Ring tempts you.

Andúril, Flame of the West

Equipped creature gets +3/+1.
Whenever equipped creature attacks, create two tapped 1/1 white Spirit creature tokens with flying. If that creature is legendary, instead create two of those tokens that are tapped and attacking.
Equip {2}

Stalwarts of Osgiliath

When this creature enters, the Ring tempts you.
Whenever you draw your second card each turn, put a +1/+1 counter on this creature.

Second Breakfast

Up to two target creatures each get +2/+1 until end of turn. Create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this token: You gain 3 life.")

Snarling Warg

Menace (This creature can't be blocked except by two or more creatures.)
As long as you control a Goblin or Orc, this creature gets +1/+0.

Mirkwood Bats

Flying
Whenever you create or sacrifice a token, each opponent loses 1 life.

Protector of Gondor

When this creature enters, create a 1/1 white Human Soldier creature token.

Haunt of the Dead Marshes

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

Rosie Cotton of South Lane

When Rosie Cotton enters, create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this token: You gain 3 life.")
Whenever you create a token, put a +1/+1 counter on target creature you control other than Rosie Cotton.