13,394 NPCs

Classic reference; current Forever availability is unconfirmed.

NPCLevelTitleZone
Lady Blaumeux63Naxxramas
Skeletal Steed61Naxxramas
Larva1Naxxramas
Gurky1Ironforge
Garel Redrock35Ironforge
Tidelord Rrurgaz62Dustwallow Marsh
Spirit of Lord Valthalak63Blackrock Spire
Kwee Q. Peddlefeet1Undercity
Tharl Stonebleeder35Orgrimmar
Theldren Trigger1
Mor Grayhoof60Blackrock Spire
Naxxramas Trigger1Naxxramas
Rousch48Hillsbrad Foothills
Dirk Thunderwood60Silithus
Durik30Stable MasterStranglethorn Vale
Gnashjaw60Malgen Longspear's Pet
Steamwheedle Bruiser55Tirisfal Glades
Isalien60
Ysida's Trigger1Stratholme
Jarien59–60Stratholme
Sothos60Stratholme
Aristan Mottar5Stormwind City
Evert Sorisam5Stormwind City
Apothecary Staffron Lerent5Royal Apothecary SocietyAlterac Mountains
Fenstad Argyle5Undercity
Mara Rennick5Undercity
Korfax, Champion of the Light60Brotherhood of the LightEastern Plaguelands
Father Inigo Montoy60Brotherhood of the LightEastern Plaguelands
Scarlet Commander Marjhan60The Scarlet CrusadeEastern Plaguelands
Commander Eligor Dawnbringer60Brotherhood of the LightEastern Plaguelands
Archmage Angela Dosantos60Brotherhood of the LightEastern Plaguelands
Plagued Swine60Eastern Plaguelands
Kormok58–60Scholomance
Rohan the Assassin60The Scarlet CrusadeEastern Plaguelands
Huntsman Leopold60The Scarlet CrusadeEastern Plaguelands
Mataus the Wrathcaster60The Scarlet CrusadeEastern Plaguelands
Rimblat Earthshatter60Earthen RingEastern Plaguelands
Rayne60Cenarion CircleEastern Plaguelands
Naxxramas Military Sub-Boss Trigger1Naxxramas
Ghoul Berserker59–60

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.