Gym Leader: Sabrina (Saffron City)

Pokémon:

• Kadabra (Level 38): Psychic
• Mr. Mime (Level 37): Psychic
• Venomoth (Level 38): Bug/Poison
• Alakazam (Level 43): Psychic

Weaknesses:

Psychic-types are weak to Bug and Ghost-type moves. Venomoth (Bug/Poison) is weak to Fire, Flying, Psychic, and Rock.

Strategy:

Sabrina's Psychic-type Pokémon are incredibly fast and hit hard with 'Psychic'. Your best counter is a strong Bug-type or Ghost-type. However, pure Ghost-types are rare and weak in Gen 1 (Gastly/Haunter/Gengar are Ghost/Poison, making them weak to Psychic). Bug-type moves are also generally weak in Gen 1.

The most reliable strategy is to use your own powerful Psychic-type Pokémon (if you have one) or strong Normal-type attackers with high Attack stats that can out-damage her. Snorlax with 'Body Slam' or 'Hyper Beam' can be effective. Alternatively, a Jolteon with 'Pin Missile' (Bug-type move, though weak) or a strong Fire-type against Venomoth can help. Be prepared for a tough fight and use Full Restores.

Reward:

Marsh Badge, TM46 (Psywave)