Essence of Horror

One of four essences used to craft Crystal Disk of Dreams for unlocking the Suppressed Power on:

The Mindsunder loot

 * Death's Touch - Unholy Burst, Greater Necromancy Focus
 * Dream Edge - Lesser Vampirism
 * Elocator's Habiliment - Greater Nimbleness
 * Gloves of Titan's Grip -, , Repair Systems
 * Light and Darkness - DR 5/Epic, Bashing
 * Quorforged Docent of Battle - Superior False Life, Toughness
 * Rahl's Might
 * Axiomatic version - Axiomatic Burst
 * Bleed version - Puncturing
 * Force version - Force Burst
 * Impact version - Maiming
 * Shock version - Shocking Burst
 * Regalia of the Phoenix - Greater Evocation Focus,
 * Terror -, Deception

The Reaver's Fate loot

 * Dreamspitter - Holy

Unique Items with Non-Unique Locations
"Any newly generated Ioun Stones will have suppressed power." - developer Eladrin

"The intention was to make the Ioun Stones 'Bound to Account on Upgrade, but Binds to a Character on Equip', but that didn't work so well and I apparently mashed random buttons in the minimum level column. (...) Let's put them into the 'may be subject to change, but no rush' bucket." - developer Eladrin
 * This item.. - ...becomes this item when unsuppressed
 * Dark Blue Ioun Stone -, (ML: 5 BtC)
 * Deep Red Ioun Stone - Dexterity Skills - Exceptional Bonus +1 (ML: 5, BtC)
 * Dusty Rose Ioun Stone - (ML5, BtC)
 * Incandescent Blue Ioun Stone -, Wisdom Skills - Exceptional Bonus +1 (ML: 5, BtC)
 * Pale Blue Ioun Stone -, Strength Skills - Exceptional Bonus +1 (ML: 5, BtC)
 * Pale Lavender Ioun Stone - (ML: 5, BtC)
 * Pink Ioun Stone -, Constitution Skills - Exceptional Bonus +1 (ML: 5, BtC)
 * Pink and Green Ioun Stone -, Charisma Skills - Exceptional Bonus +1 (ML: , BtC)
 * Scarlet and Blue Ioun Stone -, Intelligence Skills - Exceptional Bonus +1 (ML: 5, BtC)
 * Vibrant Purple Ioun Stone -, (ML: 5, BtC)

Can drop from the end chest of Eye of the Titan