Dalizapa Passage, Glaseado Mountain, Levincia, North Province (Area One), West Province (Area One) — 5 locations on the interactive map.
Mossfell Confluence, Oni Mountain — 2 locations on the interactive map.
Pokémon Tower — 1 location on the interactive map.
Rock Tunnel, Route 8 — 2 locations on the interactive map.
Gastly → Haunter (Level 25) → Gengar (Trade)