13,394 NPCs

Classic reference; current Forever availability is unconfirmed.

NPCLevelTitleZone
Wildspawn Betrayer55–56Dire Maul
Wildspawn Felsworn55–56Dire Maul
Wildspawn Shadowstalker56Dire Maul
Wildspawn Hellcaller56–57Dire Maul
Petrified Treant57–59Dire Maul
Ironbark Protector57–59Dire Maul
Alzzin's Minion56Dire Maul
Warpwood Guardian57–58Dire Maul
Warpwood Treant54–55Dire Maul
Warpwood Tangler55–56Dire Maul
Warpwood Stomper57–58Dire Maul
Highborne Summoner55Dire Maul
Tsu'zee59Dire Maul
Eldreth Seether58–59Dire Maul
Eldreth Sorcerer58–59Dire Maul
Eldreth Apparition57–58Dire Maul
Eldreth Spirit57–58Dire Maul
Eldreth Spectre58–59Dire Maul
Eldreth Phantasm58–59Dire Maul
Skeletal Highborne57–58Dire Maul
Rotting Highborne58–59Dire Maul
Arcane Aberration59–60Dire Maul
Mana Remnant57–59Dire Maul
Residual Monstrosity59–60Dire Maul
Prince Tortheldrin60–61Dire Maul
Magister Kalendris60Dire Maul
Illyanna Ravenoak60Dire Maul
Tendris Warpwood60Dire Maul
Zevrim Thornhoof57Dire Maul
Old Ironbark58Dire Maul
Alzzin the Wildshaper58Dire Maul
Immol'thar61Dire Maul
Skarr the Unbreakable58Feralas
King Gordok61–62Dire Maul
Ragnaros63Molten Core
Timbermaw Warder53–54Felwood
Oggleflint16Ragefire ChieftainRagefire Chasm
Jergosh the Invoker16Ragefire Chasm
Bazzalan16Ragefire Chasm
Taragaman the Hungerer16Ragefire Chasm

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.