All-Seer's Eye
Source: Vendor. Okay, I have finally collected this item and figured out what it does. It is essentially a priest's mind vision that lasts for 1 minute on a 30 minute cooldown.
The 
All-Seer's Eye is a Legion toy purchased from a vendor in the Antoran Wastes using 
Sightless Eyes, which are farmed from demons in the area.
Guide awaiting review
Locate Orix the Seer
Head to 60.0, 45.3 in the Antoran Wastes, where a small cave sits beside the fel river. Inside, Orix the Seer sells the All-Seer's Eye toy for Sightless Eye 1000 Sightless Eyes.
Farm Sightless Eyes
Travel north to the demon area between at 62, 23 and at 59, 23 in the Antoran Wastes, where 8–10 demons are clustered together. Running the loop takes roughly 20 seconds, and killing all demons in the area causes 1–3 to immediately respawn, making the effective respawn timer nearly instant and allowing continuous farming until you reach 1000 Sightless Eyes.
Tips
When you use the All-Seer's Eye, it functions like a priest's Mind Vision, letting you see through a targeted player's perspective for 1 minute on a 30-minute cooldown. During the channel, a button appears in the middle of your screen that sends the target a random pre-written whisper, such as "Did you mean to do that?" or "Some demons enjoy standing in the fire... you should try it sometime."
