Obsidian Sanctum

Tenebron
Vesperon
Shadron
Sartharion

http://www.wowwiki.com/Obsidian_Sanctum

Utgarde Pinnacle

Svala Sorrowgrave
Gortok Palehoof
Skadi the Ruthless
King Ymiron

http://www.wowwiki.com/Utgarde_Pinnacle

Utgarde Keep

Prince Keleseth
Skarvald & Dalronn
Ingvar the Plunderer

http://www.wowwiki.com/Utgarde_Keep

Oculus

Drakos the Interrogator
Varos Cloudstrider
Mage-Lord Urom
Ley-Guardian Eregos

http://www.wowwiki.com/Oculus

Nexus

Commander Kolurg ( Heroic)
Commander Stoutbeard ( Heroic)
Grand Magus Telestra
Anomalus
Ormorok the Tree-Shaper
Keristrasza

http://www.wowwiki.com/Nexus

Gundrak

Slad'ran
Moorabi
Drakkari Colossus
Gal'darah
Eck the Ferocious (Heroic)

http://www.wowwiki.com/Gundrak

Azjol-Nerub

Krik'thir the Gatewatcher
Hadronox
Anub'arak

http://www.wowwiki.com/Azjol-Nerub_%28instance%29

Ahn'kahet: The Old Kingdom

Elder Nadox
Prince Taldaram
Jedoga Shadowseeker
Amanitar (heroic only)
Herald Volazj

http://www.wowwiki.com/Ahn%27kahet:_The_Old_Kingdom

Ulduar (instance)

Flame Leviathan
Ignis the Furnace Master
Razorscale
XT-002 Deconstructor
The Assembly of Iron
Kologarn
Auriaya
Mimiron
Freya
Thorim
Hodir
General Vezax
Yogg-Saron
Algalon the Observer

http://www.wowwiki.com/Ulduar_%28instance%29

Halls of Lightning

General Bjarngrim
Volkhan
Ionar
Loken

http://www.wowwiki.com/Halls_of_Lightning

Halls of Stone

Maiden of Grief
Krystallus
Tribunal of Ages
Sjonnir The Ironshaper

http://www.wowwiki.com/Halls_of_Stone