13,394 NPCs

Classic reference; current Forever availability is unconfirmed.

NPCLevelTitleZone
Clunk48The UndermarketSearing Gorge
Skeletal Servant32Stratholme
Kalaran Windblade55Searing Gorge
Liv Rizzlefix17Workshop AssistantThe Barrens
Nightmare Suppressor49–50The Temple of Atal'Hakkar
Gibblewilt11Dun Morogh
Dark Iron Sentry48Searing Gorge
Tymor35Ironforge
Gretta Ganter10Fisherman SuppliesDun Morogh
Squire Maltrake52Searing Gorge
Belnistrasz36Razorfen Downs
Xiggs Fuselighter45Ironforge
Rynthariel the Keymaster29Stonetalon Mountains
Blighted Surge54–55Eastern Plaguelands
Plague Ravager55–56Eastern Plaguelands
Blighted Horror56–57Eastern Plaguelands
Plague Monstrosity57–58Eastern Plaguelands
Scourge Soldier53–54Eastern Plaguelands
Cursed Mage54–55Eastern Plaguelands
Scourge Warder55–56Eastern Plaguelands
Dark Caster56–57Eastern Plaguelands
Scourge Guard57–58Eastern Plaguelands
Dread Weaver58–59Eastern Plaguelands
Scourge Champion59–60Eastern Plaguelands
Cannibal Ghoul54–55Eastern Plaguelands
Gibbering Ghoul56–57Eastern Plaguelands
Diseased Flayer57–59Eastern Plaguelands
Putrid Gargoyle54–56Eastern Plaguelands
Putrid Shrieker56–57Eastern Plaguelands
Unseen Servant55–56Eastern Plaguelands
Eyeless Watcher57–58Eastern Plaguelands
Torn Screamer53–55Eastern Plaguelands
Hate Shrieker55–57Eastern Plaguelands
Death Singer57–59Eastern Plaguelands
Stitched Horror57–58Eastern Plaguelands
Gangled Golem58–59Eastern Plaguelands
Abomination59–60Eastern Plaguelands
Dark Adept59Cult of the DamnedEastern Plaguelands
Death Cultist53–54Cult of the DamnedEastern Plaguelands
Vile Tutor56–57Cult of the DamnedEastern Plaguelands

Classic reference data from QuestieDB (Forever data, commit c5de61a), with positions on Forever's zone maps. It doesn't confirm that an NPC, location, quest or item is in Forever.