Elven-light can only be played from your discard pile.

Action: Return Elven-light to your hand from your discard pile. Then, draw 1 card.

Then Aragorn was abashed, for he saw the elven–light in her eyes and the wisdom of many days...
–The Return of the King

As an additional cost to play Skyward Volley, exhaust a ranged character you control.

Combat Action: Deal 2 damage to an enemy engaged with a player. Resolve that effect again for each copy of Skyward Volley currently in your discard pile (you may choose different targets).

Response: After an enemy is declared as an attacker against you, declare an exhausted character you control as the defender. Resolve that effect again for each copy of Anchor Watch currently in your discard pile (all chosen characters are defending against this attack).

Action: Place 2 progress on any location. Resolve that effect again for each copy of The Evening Star currently in your discard pile (you may choose new targets).

...for ever still a herald on
an errand that should never rest
to bear his shining lamp afar,
the Flammifer of Westernesse.
–The Fellowship of the Ring

Quest Action: Ready a questing character and give that character +1 until the end of the phase. Resolve that effect again for each copy of Elwing’s Flight currently in your discard pile (you may choose different targets).

There flying Elwing came to him
and flame was in the darkness lit;
more bright than light of diamond
the fire upon her carcanet.
–The Fellowship of the Ring

Glorfindel can be played from your discard pile.

Action: Discard a card from your hand to ready Glorfindel. (Limit once per phase.)

"He is an Elf-lord of a house of princes."
–Gandalf, The Fellowship of the Ring

Veteran Sword-elf gets +1 and +1 for each copy of Veteran Sword-elf in your discard pile.

The elves were the first to charge. Their hatred for the goblins is cold and bitter.
–The Hobbit

You may exhaust any number of Healer characters you control as part of this card's cost. Reduce the cost to play this card by 1 for each Healer character you exhaust in this way.

Refresh Action: Choose a hero in any player's discard pile. Put that hero into play under its owner's control, with 1 damage token on it.

Attach to Kahliel. Restricted.

Each Harad character gets +1 .

Refresh Action: Exhaust Kahliel’s Headdress to shuffle the topmost Harad ally in your discard pile into your deck.

Combat Action: Choose a Beorning ally with printed cost 3 or more in your hand or discard pile. Discard Beorning Skin-changer to put that ally into play.

"...sometimes he is a huge black bear, sometimes he is a great strong black–haired man with huge arms and a great beard."
–Gandalf, The Hobbit

Response: After Knight of Belfalas enters play, return a Gondor ally from your discard pile to your hand.

The mounted knights returned, and at their rear the banner of Dol Amroth...
–The Return of the King

Action: If you control at least 1 Dwarf hero, put a Dwarf ally from your discard pile into play under your control. Put that ally on the bottom of your deck at the end of the phase.

Out leapt the King under the Mountain, and his companions followed him. –The Hobbit

While there is a hero in your discard pile, Prince Imrahil loses the ally card type and gains the hero card type.

"We must gather all of the strength that we can find.
–The Return of the King

Attach to a Rohan hero. Restricted.

Response: After attached hero is declared as an attacker, exhaust Gúthwinë to give that hero +2 for this attack. If this attack destroys an enemy, return a Rohan ally from your discard pile to your hand.

“Gúthwinë!” cried Éomer. “Gúthwinë for the Mark!”
–The Two Towers