Ascended Commendation

Ascended Commendations are rewarded by various quests and world quests. When a quest that grants an Ascended Commendation is completed, you automatically receive reputation with the Ascended.

Source
Bastion world quests (+175 reputation):

Ta'lan the Antiquary weekly quests (+500 reputation):
 * A Valuable Find: Plaguefall
 * A Valuable Find: The Other Side

Finder Ta'sul weekly quests (+500 reputation):
 * Trading Favors: Plaguefall

Trivia

 * Early in the Shadowlands beta, the Trading Favors quests awarded Kyrian Armaments instead.