Main Games
Professor Oak (Kanto) · Professor Elm (Johto)
Professor Birch (Hoenn) · Professor Rowan (Sinnoh) · Professor Juniper (Unova)
Pokémon Ranger & Shadow Games
Professor Krane (Orre) · Professor Hastings (Fiore/Almia/Oblivia)
Anime
Professor Ivy (Orange Islands)