Diablo II: Lord of Destruction/Animal

Abominable

 * Drifter Cavern
 * Ancients' Way
 * Icy Cellar

Snow Drifter

 * Crystalline Passage
 * Frozen River
 * Glacial Trail

Arach

 * Halls of Vaught
 * Forgotten Sands
 * Forgotten Sands

Enslaved

 * Bloody Foothills
 * Frigid Highlands
 * Frozen Tundra

Slayer

 * Frigid Highlands
 * Halls of Vaught

Hell Spawn

 * Abaddon

Fire Boar

 * Arreat Plateau
 * Infernal Pit
 * Worldstone Keep Level 3

Ice Spawn

 * Halls of Vaught

Greater Hell Spawn

 * Worldstone Keep Level 2

Temple Guard

 * Halls of Anguish
 * Halls of Pain

Night Marauder

 * Halls of Vaught

Gloombat

 * Glacial Trail
 * Icy Cellar

Fiend

 * Worldstone Keep Level 2

Blood Lord

 * Abaddon
 * Pit of Acheron
 * Crystalline Passage

Moon Lord

 * Glacial Trail
 * Drifter Cavern

Night Lord

 * Halls of Anguish
 * Halls of Pain
 * Infernal Pit

Hell Lord

 * Ancients' Way
 * Icy Cellar

Death Lord

 * Worldstone Keep Level 1
 * Worldstone Keep Level 3
 * Throne of Destruction

Blood Maggot

 * Halls of Pain
 * Forgotten Sands
 * Forgotten Sands

Blood Maggot Egg

 * Halls of Pain
 * Forgotten Sands
 * Forgotten Sands

Blood Maggot Young

 * Halls of Pain
 * Forgotten Sands
 * Forgotten Sands

Carrion Bird

 * Bloody Foothills
 * Frozen Tundra

Claw Viper

 * Crystalline Passage
 * Frozen River

Salamander

 * Pit of Acheron
 * Infernal Pit

Pit Viper

 * Glacial Trail
 * Icy Cellar

Tomb Viper

 * Halls of Vaught

Serpent Magus

 * Worldstone Keep Level 2
 * Throne of Destruction

Death Mauler

 * Bloody Foothills

Death Brawler

 * Frigid Highlands

Death Slasher

 * Arreat Plateau

Death Brigadier

 * Halls of Anguish

Death Berserker

 * Frozen Tundra

Foul Crow

 * Bloody Foothills

Frozen Creeper

 * Crystalline Passage
 * Frozen River
 * Glacial Trail

Frozen Terror

 * Drifter Cavern
 * Ancients' Way
 * Icy Cellar

Hell Swarm

 * Forgotten Sands
 * Forgotten Sands

Hierophant

 * Halls of Pain
 * Worldstone Keep Level 1

Cave Leaper

 * Crystalline Passage

Tomb Creeper

 * Halls of Anguish

Saber Cat

 * Frozen Tundra

Infidel

 * Crystalline Passage
 * Drifter Cavern
 * Halls of Pain

Invader

 * Worldstone Keep Level 1

Assailant

 * Throne of Destruction

Scarab

 * Halls of Anguish

Steel Scarab

 * Worldstone Keep Level 2
 * Forgotten Sands
 * Forgotten Sands

Siege Beast

 * Frigid Highlands

Blood Bringer

 * Arreat Plateau

Crush Beast

 * Frozen Tundra

Slinger

 * Bloody Foothills
 * Frigid Highlands
 * Arreat Plateau

Spike Fiend

 * Ancients' Way

Quill Rat

 * Bloody Foothills

Razor Spine

 * Halls of Pain

Fanatic Enslaved

 * Bloody Foothills
 * Frigid Highlands

Berserker Slayer

 * Frigid Highlands

Consumed Ice Boar

 * Frigid Highlands

Consumed Fire Boar

 * Arreat Plateau
 * Infernal Pit
 * Worldstone Keep Level 3

Frenzied Ice Spawn

 * Halls of Vaught
 * Worldstone Keep Level 2

Thorned Hulk

 * Bloody Foothills

Zealot

 * Halls of Pain
 * Worldstone Keep Level 1