The following NPCs can be found in Coilfang Reservoir.
Questgivers[]
Neutral[]
Luma Skymother (Dungeon: The Slave Pens, Midsummer Fire Festival only)
[1-70] Summon Ahune (Daily, Dungeon: The Slave Pens, Midsummer Fire Festival only)
Numa Cloudsister (Dungeon: The Slave Pens, Midsummer Fire Festival only)
[1-70] Ahune is Here! (Daily, Dungeon: The Slave Pens, Midsummer Fire Festival only)
Orders from Lady Vashj (Dungeon: The Steamvault)
[70D] Orders from Lady Vashj (Dungeon: The Steamvault)
Seer Olum (Raid: Serpentshrine Cavern)
[30] The Secret Compromised (Raid: Serpentshrine Cavern)
Skar'this the Heretic (Dungeon: The Slave Pens, Heroic) only)
[30R] The Mark of Vashj (Dungeon: The Slave Pens, Heroic) only)
[30R] The Cudgel of Kar'desh (Dungeon: The Slave Pens, Heroic) only) (Raids: Gruul's Lair and Karazhan)
[Shards of Ahune] (Dungeon: The Slave Pens, Midsummer Fire Festival only)
[1-70] Shards of Ahune (Dungeon: The Slave Pens, Midsummer Fire Festival only)
Watcher Jhang (Outside instance portals)
[10-30D] Lost in Action (Dungeons: The Slave Pens and the Underbog)
[70D] The Warlord's Hideout (Dungeon: The Steamvault)
Bosses[]
Ahune <The Frost Lord> (Dungeon: The Slave Pens, Midsummer Fire Festival only)
Fathom-Lord Karathress (Raid: Serpentshrine Cavern)
Ghaz'an (Dungeon: The Underbog)
Hungarfen (Dungeon: The Underbog)
Hydromancer Thespia (Dungeon: The Steamvault)
Hydross the Unstable <Duke of Currents> (Raid: Serpentshrine Cavern)
Lady Vashj <Coilfang Matron> (Raid: Serpentshrine Cavern)
Leotheras the Blind (Raid: Serpentshrine Cavern)
Mekgineer Steamrigger (Dungeon: The Steamvault)
Mennu the Betrayer (Dungeon: The Slave Pens)
Morogrim Tidewalker (Raid: Serpentshrine Cavern)
Quagmirran (Dungeon: The Slave Pens)
Rokmar the Crackler (Dungeon: The Slave Pens)
Swamplord Musel'ek (Dungeon: The Underbog)
The Black Stalker (Dungeon: The Underbog)
The Lurker Below (Raid: Serpentshrine Cavern)
Warlord Kalithresh (Dungeon: The Steamvault)
Merchants[]
Neutral[]
Mortog Steamhead (Outside instance portals, requires Cenarion Expedition: Exalted)
Other Notable NPCs[]
Neutral[]
Earthbinder Rayge (Dungeon: The Underbog)
Naturalist Bite (Dungeon: The Slave Pens)
Weeder Greenthumb (Dungeon: The Slave Pens)
Windcaller Claw (Dungeon: The Underbog)
Hostile[]
Claw <Swamplord Musel'ek's Pet> (Dungeon: The Underbog)
Fathom-Guard Caribdis (Raid: Serpentshrine Cavern)
Fathom-Guard Sharkkis (Raid: Serpentshrine Cavern)
Fathom-Guard Tidalvess (Raid: Serpentshrine Cavern)