13,394 NPCs

Classic reference; current Forever availability is unconfirmed.

NPCLevelTitleZone
Highland Horror28Wetlands
Highland Tortoise26Wetlands
Frezzlie PopwhizUnknownNewly Promoted Overseer of Slime ExperimentsMount Hyjal
Tainted Grovewalker57Mount Hyjal
Phoebe HighfeatherUnknownMount Hyjal
Zarrat WormwingUnknown
TazzikUnknownTanaris
Sentry ChildersUnknownRiverglades
Twilight MaulerUnknownRiverglades
Twilight InstigatorUnknown
KlunkUnknown
Vile Moonwell OozeUnknown
Crag'rogUnknownRiverglades
Ogre MinerUnknownRiverglades
Twilight SubjugatorUnknownRiverglades
Bonzo "The Brain" GreasepitUnknownThe Undermarket
Ka'ya SpeartuskUnknownUndermarket Bounty Hunter
Liu the LookoutUnknownThe Undermarket
Cadrya BalenUnknownThe Undermarket
Scrapper FrazziUnknownThe Undermarket
Faldrim AnvilmarUnknown
PlunderUnknown
NalukUnknownButcherRiverglades
MagmatusUnknown
Durgen DirgehammerUnknownThe Hall of Thanes
Brimstone BellmanUnknownThe Undermarket
Walton20TannerThe Barrens
Terry Longdrink19Bounty HunterThe Barrens
Kul Tiras Marine16–18The Barrens
Vrang Wildgore35Weaponsmith & ArmorcrafterThe Barrens
Theramore GuardUnknownDustwallow Marsh
Riding Striped FrostsaberUnknownDarnassus
Gaznik GearsnapsUnknownZeppelin Operator
Riding Striped NightsaberUnknownDarnassus
Riding Spotted FrostsaberUnknownDarnassus
Diseased Forest WalkerUnknown
Webbed Mudsnout GnollUnknownHillsbrad Foothills
Gorgrash24Escaped Durnholde PrisonerHillsbrad Foothills
HekshiUnknownZandalar InfiltratorStranglethorn Vale
Sister RowlandUnknownRiverglades

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.