13,394 NPCs

Classic reference; current Forever availability is unconfirmed.

NPCLevelTitleZone
Argent Messenger55The Argent DawnUndercity
Commander Thomas Helleran55The Argent DawnEastern Plaguelands
Master Craftsman Omarion60Brotherhood of the LightNaxxramas
Necropolis Acolyte62Naxxramas
Craftsman Wilhelm57Brotherhood of the LightEastern Plaguelands
Argent Sentry60The Argent DawnEastern Plaguelands
Spirit of the Damned61
Bone Witch61
Archmage Tarsis Kir-Moldir60Naxxramas
Flameshocker53–55
Argent Dawn Initiate1The Argent DawnUndercity
Necropolis Relay1Winterspring
Captain Armando Ossex60Alterac Mountains
Argent Dawn Paladin1The Argent DawnStormwind City
Necropolis Proxy1Winterspring
Bloodsail Traitor43–44Stranglethorn Vale
Toxic Tunnel61Naxxramas
Necropolis60Winterspring
Bronn Fitzwrench55–56Winterspring
Rumsen Fizzlebrack44Tanaris
Mupsi Shacklefridd20The Barrens
Necropolis health1Winterspring
Skeletal Soldier6–7Elwynn Forest
Spectral Apparition6–7Elwynn Forest
Cracked Necrotic Crystal60
Argent Dawn Crusader1The Argent DawnStormwind City
Argent Dawn Champion1The Argent DawnStormwind City
Argent Dawn Cleric1The Argent DawnUndercity
Argent Dawn Priest1The Argent DawnUndercity
Spectral Spirit9–10Durotar
Skeletal Trooper9–10Teldrassil
Plagued Gargoyle61Naxxramas
Plagued Ghoul61Naxxramas
Plagued Deathhound61Naxxramas
Spirit of Naxxramas61Naxxramas
Deathknight Vindicator62Naxxramas
Necro Knight Guardian62Naxxramas
Necro Stalker61Naxxramas
Innkeeper Faralia30InnkeeperStonetalon Mountains
Lieutenant Orrin10The Argent DawnStormwind City

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.