There's a whole bunch of new patterns to pick up in Phase 3 of World of Warcraft: Season of Discovery. Here's a list of all the locations and steps to get what you need to craft your own Nightmare items.
How to Get EPIC Crafting Recipes in Phase 3 [WoW SoD]
There are 19 new items that can be crafted through the various professions available to SoD players. Most of these require an item called the Inert Mantle of Nightmares and Nightmare Seeds. You can purchase Mantles from Rix Xizzix in Booty Bay, while Seeds are dropped by Sunken Temple enemies. Here's a quick look at each of these 19 items, how to craft them, and a brief description of what they do.
Related: How to Get the Ancestral Sword in WoW Season of Discovery
The first step of the quest chain will be in the Ashenvale Nightmare Incursion. Search the dream for the Warsong Lumber Camp and then head south. Avoid the bridge and keep heading south until you receive the debuff called the Aura of Paralyzing Dread from the Nightmare Amalgamation (87.35; see map above). When you receive it, your chatbox will display "Drink your fear… drink your pain…". Get out of the Emerald Nightmare and head to Ashenvale Field Captain Hannalah (map below).