Head Hunting: Horrors of the Forge

This quest is unlocked by reaching Renown level 11 of the Manaforge Vandals. This requires to kills the 4 minibosses in the Raid, in any difficulty. These can be found in the following LFR wings:

Might of the Shadowguard

• 
  
• [npc=239454]: Right after the first boss Plexus Sentinel
• 
  

Monsters of the Sands:

• 
  
• [npc=239702]: On your way to Forgeweaver Araz
• 
  
• [npc=245617]: Right before Factillus
• 
  

Heat of Darkness:

• 
  
• [npc=245601]: Right before Nexus-King Salhadaar
• 
  

Offered automatically within the [zone=16178] raid at [faction=2736] Renown level 11.

The Warbound items mentioned in the rewarded spell [spell=1243678] are Warbound versions of the BoEs from Manaforge (alt link if the first one breaks) and these mostly are the only way to obtain class-agnostic lookalikes of some items, excluding the Boots (sharing appearances with the respective Reshii Boots) and the Ring of course.
This can help obtaining appearances you otherwise only get from the BoE items, and I hope they carry this mechanic forward.
Notable appearances are lookalikes of the Mage Hat and the Warrior Helm.

As Warbound items, they drop one track down from the difficulty you obtain them from, e.g. in Mythic difficulty you get a Hero-track item, but until Midnight fully launches and ends TWW Season 3, you can still upgrade them to 5/8 for the higher-difficulty appearance. After the season ends, Mythic appearances won't be obtainable that way, so only the BoEs obtained from trash in Mythic Manaforge (or the AH) remain as sources.