1. Misty of Cerulean City - Misty is a tough Gym Leader to beat, as she has a wide variety of Pokémon that she can use in battle. Her Gyarados is particularly dangerous, and her Poliwrath can also be a formidable foe.
  2. Lt. Surge of the Viridian Gym - Lt. Surge is one of the most difficult Gym Leaders to face in the game, as he has a wide variety of powerful Pokémon at his disposal. His Raichu can easily take down most opponents, while his Jolteon and Flareon are also very dangerous foes.
  3. Blaine of the Indigo Plateau - Blaine is one of the most challenging Gym Leaders in the game, as he has a wide variety of powerful Pokémon at his disposal. His Machamp can easily take down most opponents, while his Geodude and Golem are also very tough foes to beat.
  4. Brock of Pewter City - Brock is another tough Gym Leader to face in the game, as he has a wide variety of powerful Pokémon at his disposal. His Onix can easily take down most opponents, while his Geodude and Golem are also very tough foes to beat.
  5. Erika of Lavender Town - Erika is one of the toughest Gym Leaders in the game, as she has a wide variety of powerful Pokémon at her disposal. Her Dragonite can easily take down most opponents, while her Machamp and Venusaur are also very dangerous foes to face off against ..