The new The Enlightened reputation from Zereth Mortis is extremely important. It provides access to a 2nd legendary in any slot and other various recipes and items that can make a raider's life easier. The following items are relevant to raiders:
Friendly: Font of Ephemeral Power, a BoP item that unlocks all conduits at 226.
Honored: Tome of the Eternal, which is the recipe to create Vestiges of the Eternal in order to craft ilvl 291 legendaries. Requires completion of Chapter 5 on week 3 of the patch. Updated 2/21/22
Honored: Crafter’s Mark of the First Ones, which allows you to create ilvl 262 unique equipped items.
Revered: Contract: The Enlightened recipe for Scribes. Scribes can craft this and sell it on the auction house, allowing people to gain 10 additional rep from World Quests.
Revered: Memory of Unity, which gives you account-wide access to crafting your Covenant legendary power on any slot in addition to allowing you to equip a second Legendary. Also requires completing Chapter 7 of the patch storyline.
Exalted: Eternal Augment Rune, an infinitely reusable Augment Rune.
Exalted: Vessel of Profound Possibilities Update 2/16: This item no longer requires reputation and will instead be from your Covenant vendor.
Here’s how you can increase your reputation with The Enlightened:
World Quests: There are 3 world quests per day in Zereth Mortis that provide 125 reputation. In addition, some of these world quests will provide a 75 rep token as a reward.
Weekly Quests: There is 1 weekly quest to kill the new world boss for 500 reputation and a quest similar to Shaping Fate that gives 250 reputation that can be done twice a week.
Daily Quests: When you first start in Zereth Mortis, you will have access to 2 daily quests per day. You can gain more daily quests by upgrading your Cypher Console. These dailies have a chance of rewarding a commendation that gives 75-100 per commendation.
Rares: Rares give a small amount of reputation - 10 to 15 per rare.
Contract: Once a scribe reaches Revered with The Enlightened, they can craft a Contract for the Enlightened that provides 10 reputation per world quest completed in any zone. This means you can do a world tour of world quests and gain a couple hundred rep per day. The contract requires Friendly to use but the Scribe must be revered to craft it.