One known PH is in the mephit caves at location +39, -425, -55. It's also been known to spawn from other mobs around this location.
Brightly Pulsating Crystallized Cosgrove Shard
Damascite Encrusted Brachial Clay
Damascite Encrusted Carpal Clay
Damascite Encrusted Cephalic Clay
Damascite Encrusted Phalangeal Clay
Damascite Encrusted Tarsal Clay
Dimly Pulsating Crystallized Cosgrove Shard
Earring of Delightful Pain
Earring of the Halfmoon
Hardened Sessiloid Tear
Mephit Wing Sample
Pulsating Crystallized Cosgrove Shard
Ring of Righteous Slaying
Ring of Uncertain Fate
Strong Captured Cliknar Mount Saddle