Diablo II: Lord of Destruction/Undead

Undead Stygian Doll

 * Abaddon
 * Icy Cellar

Undead Soul Killer

 * Throne of Destruction

Cadaver

 * Worldstone Keep Level 2

Doom Knight

 * Infernal Pit
 * Worldstone Keep Level 3
 * Throne of Destruction
 * Furnace of Pain
 * Furnace of Pain

Strangler

 * Abaddon

Storm Caster

 * Worldstone Keep Level 3

Unraveler

 * Pit of Acheron

Guardian

 * Halls of Pain

Horadrim Ancient

 * Worldstone Keep Level 2
 * Throne of Destruction

Oblivion Knight

 * Infernal Pit
 * Worldstone Keep Level 3
 * Throne of Destruction
 * Furnace of Pain
 * Furnace of Pain

Reanimated Horde

 * Ancients' Way

Rot Walker

 * Frozen River
 * Glacial Trail

Prowling Dead

 * Nihlathak's Temple
 * Halls of Anguish
 * Halls of Vaught

Unholy Corpse

 * Infernal Pit
 * Worldstone Keep Level 1

Bone Warrior

 * Glacial Trail

Returned

 * Halls of Anguish
 * Tristram
 * Tristram

Burning Dead Archer

 * Bloody Foothills
 * Frigid Highlands

Horror Archer

 * Abaddon
 * Tristram
 * Tristram

Returned Archer

 * Halls of Vaught

Bone Archer

 * Frozen Tundra

Returned Mage

 * Arreat Plateau (Fire and Lightning)
 * Frozen Tundra (Lightning)

Burning Dead Mage

 * Pit of Acheron (Fire)
 * Tristram (Fire)
 * Tristram (Fire)

Bone Mage

 * Crystalline Passage (Cold)
 * Frozen River (Cold)
 * Glacial Trail (Cold)
 * Drifter Cavern (Cold)
 * Ancients' Way (Cold)
 * Tristram (Cold)
 * Tristram (Cold)

Horror Mage

 * Halls of Anguish (Poison)
 * Worldstone Keep Level 2 (Poison)
 * Worldstone Keep Level 3 (Lightning)
 * Tristram (Lightning and Poison)
 * Tristram (Lightning and Poison)

Death Mage

 * Throne of Destruction (Cold)

Blood Lord

 * Infernal Pit

Ghoul Lord

 * Worldstone Keep Level 1

Dark Lord

 * Throne of Destruction
 * Tristram
 * Tristram

Gloam

 * Frozen River
 * Icy Cellar

Black Soul

 * Worldstone Keep Level 2

Burning Soul

 * Throne of Destruction

Wraith

 * Glacial Trail

Ghost

 * Crystalline Passage
 * Frozen River
 * Drifter Cavern
 * Halls of Vaught
 * Icy Cellar

Specter

 * Worldstone Keep Level 3
 * Tristram
 * Tristram