13,394 NPCs

Classic reference; current Forever availability is unconfirmed.

NPCLevelTitleZone
Orok Deathbane5Orgrimmar
Temma of the Wells5Thunder Bluff
Tormek Stoneriver5Ironforge
Loatheb63Naxxramas
Mokvar60Orgrimmar
Deliana60Ironforge
Mux Manascrambler60Tanaris
Vi'el60Exotic Reagent MerchantWinterspring
Anthion Harmon60Eastern Plaguelands
Patchwork Golem61Naxxramas
Bile Retcher61Naxxramas
Mad Scientist61Naxxramas
Living Monstrosity62Naxxramas
Surgical Assistant60Naxxramas
Embalming Slime60Naxxramas
Stitched Spewer63Naxxramas
Patchwerk63Naxxramas
Sludge Belcher62Naxxramas
Maggot1Naxxramas
Ysida Harmon60Stratholme
Falrin Treeshaper60Dire Maul
Bodley60
Plague Beast61Naxxramas
Frenzied Bat60Naxxramas
Plagued Bat60Naxxramas
Lord Valthalak63Blackrock Spire
Magma Lord Bokk58–60Burning Steppes
Mor Grayhoof Trigger1Blackrock Spire
Isalien Trigger60Dire Maul
Jarien and Sothos Trigger1Stratholme
Kormok Trigger1Scholomance
Lord Valthalak Trigger60Blackrock Spire
Diseased Maggot60Naxxramas
Rotting Maggot60Naxxramas
Theldren60Blackrock Depths
Gothik the Harvester63Naxxramas
Instructor Razuvious63Naxxramas
Highlord Mograine63The AshbringerNaxxramas
Sir Zeliek63Naxxramas
Thane Korth'azz63Naxxramas

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.