Play only if you control a unique character with the Noble trait and another unique character with the Scout trait.
Response: After a player engages an enemy, reduce his threat by X, where X is that enemy's printed
...the Captains of the West were well warned by their scouts...
–The Return of the King
Play only if you control a unique character with the Ranger trait and another unique character with the Warrior trait.
Response: After you engage an enemy, that enemy cannot attack you until the end of the round.
Play only if you control a unique character with the Noble trait and another unique character with the Ranger trait.
Response: After a hero you control participates in an attack that destroys an enemy, add X resources to that hero's pool. X is the just destroyed enemy's printed
Play only if you control a unique character with the Warrior trait and another unique character with the Scout trait.
Response: After the players have committed characters to the quest, discard a non-unique enemy in the staging area. Then, reveal an encounter card.
Play only if the characters you control have a total of at least 9 different Traits between them.
Action: Ready each character in play. Until the end of the phase, each character you control gets +1 
"For the rest, they shall represent the other Free Peoples of the World: Elves, Dwarves and Men."
–Elrond, The Fellowship of the Ring
Play only if you control a unique character with the Rohan trait and another unique character with the Gondor trait.
Response: At the beginning of the combat phase, you resolve the step in which you attack enemies before resolving enemy attacks this phase. (Each other player resolves the combat phase as normal after you resolve your attacks.)
Play only if you control a unique character with the Noldor trait and another unique character with the Dúnedain trait.
Action: Choose a non-unique location in the staging area and increase your threat by X to discard it. X is the chosen location's printed quest points.
Play only if you control a unique character with the Ent trait and another unique character with the Hobbit trait.
Action: Ready each damaged Ent character you control.