The Pokémon Archive's Gym Leader List

The Pokémon Archive's Gym Leader List Gym Leaders

Brock
Location: Pewter City
Pokémon: Geodude (Lv. 12), Onix (Lv. 14)
Weakness: Grass, Water
Disadvantage: Flying, Normal, Bug Strategy: This should be a relatively easy battle- if you have a Bulbasaur or Squirtle. If you have Bulbasaur, use Vine Whip and that should do it. If you have Squirtle use Water Gun- Bang. The match should be over after you've used it on Geodude and Onix. If you have a Charmander you should build it up to Lv. 15 or evolve it into Charmeleon. A few Embers should still do it though.
Helpful Tips: Don't use any Pokémon you've caught before (E.G. Pidgey, Rattata, Caterpie, Weedle). They all have disadvantages against Rock Pokémon.

Misty
Pokémon: Staryu (Lv. 18), Starmie (Lv. 21)
Weakness: Grass, Electric
Disadvantage: Water, Rock, Ground
Strategy: The best Pokémon to use for this battle are Bulbasaur/Ivysaur, Pikachu or Ekans (Red only). Use one of those Pokémon's best physical attack (E.G. Bulb/Ivysaur: Vine Whip, Pikachu: Thundershock, Ekans: Bite). If you have a Squirtle/Wartortle use Bite if you have it. If not all that'll do well is Tackle. If you have Charmander/Charmeleon use Rage or Scratch. This may be a tough battle if you have a Charmander/Charmeleon.
Helpful Hints: If you have Squirtle/Wartortle or Charmander/Charmeleon use physical attacks.

Lt. Surge
Pokémon: Voltorb (Lv. 21), Pikachu (Lv. 18), Raichu (Lv. 24)
Weakness: Ground
Disadvantage: Water, Electric, Flying
Strategy: The 3 best Pokémon to use are Sandshrew (Blue only), Diglett and Dugtrio. Not any of the 3 starting Pokémon will have a great advantage on these Electric guys. You shouldn't have a problem catching a Ground Pokémon. I guarantee you'll catch a Ground Pokémon in Diggett Cave (There is ONLY Diglett and Dugtrio in the cave!). Still if you taught your Wartortle Body Slam it should take care of Voltorb, Pikachu and Raichu.
Helpful Hints: Use a Ground Pokémon.

Erika
Pokémon: Victreebel (Lv. 29), Tangela (Lv. 24), Vileplume (Lv. 29)
Weakness: Fire, Ice, Flying, Bug
Disadvantage: Water, Electric, Grass, Ground
Strategy: Charmeleon/Charizard or any Fire (Charizard), Ice (Jynx), Flying (Pidgeotto/Pidgeot) or Bug (Butterfree) Pokémon will do well. I listed the Pokémon I think will do best of their kind. If you have one of the disadvantaged Pokémon still something physical will do well (E.G. Bite, Body Slam). This battle shouldn't be to hard, even is you are at a disadvantage (I beat these 3 Grass Pokémon with Blastoise in 1 attack).

Sabrina
Pokémon: Kadabra (Lv. 38), Mr. Mime (Lv. 37), Venomoth (Lv. 38), Alakazam (Lv. 43)
Weakness: Bug, Ghost
Disadvantage: Psychic
Strategy: Again, use phyical attacks will put the nail in the coffin because these Pokémon have low defence ratings. If you don't want to do that try using a Bug (Beedrill) or Ghost (Gengar). This should be a quick battle.
Helpful Hints: Be physical.

Koga
Pokémon: Koffing (Lv. 37), Muk (Lv. 39), Koffing (Lv. 37), Weezing (Lv. 43)
Weakness: Ground, Psychic, Rock, Ghost
Disadvantage: Grass, Fighting, Poison
Strategy: Use special attacks in this battle, or try packing a Ground (Sandslash), Psychic (Alakazam), Rock (Golem/Onix) or Ghost Pokémon.That's all you need to know.
Helpful Hints: I just gave them to you!

Blaine
Pokémon: Growlithe (Lv. 42), Ponyta (Lv. 40), Rapidash (Lv. 42), Arcanine (Lv. 47)
Weakness: Water, Ground, Rock
Disadvantage: Grass, Bug, Flying
Strategy: Another straitforward match, Just use Water (Blastoise), Ground (Sandslash) or Rock (Omastar/Golem/Onix).
Helpful Hints: If the levels are the same or higher, almost all water will kill on the first hit.

Giovanni
Pokémon: Rhyhorn (Lv. 45), Dugtrio (Lv. 42), Nidoqueen (Lv. 43), Nidoking (Lv. 45, Rhydon (Lv. 50)
Weakness: Water, Grass, Ice, Flying
Disadvantage: Electric, Rock
Strategy: Water (Blastoise), Grass (Venusaur), Ice (Jynx) or Flying (Articuno/Pidgeot) will do in this battle. This time physical won't do much but specials will.
Helpful Hints: Good Luck!