Brock (Boulder Badge)

Misty (Cascade Badge)

Lt. Surge (Thunder Badge)

Erika (Rainbow Badge)

Grass-type gym leader in Celadon City. Fourth gym leader you will battle who specializes in grass-type Pokemon. Uses Victreebel (Level 29), Tangela (Level 24), and Vileplume (Level 29). Defeat her and she’ll give you TM21 (Mega Drain). Recommend using fire and/or flying type
Koga (Soul Badge)

Sabrina (Marsh Badge)

Psychic-type gym leader in Saffron City. Sixth gym leader who specializes in Psychic-type Pokemon. Uses Kadabra (Level 38), Mr. Mime (Level 37), Venomoth (Level 38), and Alakazam (Level 43). Defeat her and she’ll give you TM46 (Psywave). Recommend getting a Ghost-type pokemon and/or a pokemon that is raised.
Blaine (Volcano Badge)

Giovanni (Earth Badge)

Ground-type gym leader in Viridian City. Eith and final gym leader in Kanto that specializes in ground-type Pokemon. Uses Rhyhorn (Level 45), Dugtrio (Level 42), Nidoqueen (Level 44), Nidoking (Level 45), and Rhydon (Level 50). Defeat him and he’ll give you TM27 (Fissure). Recommend using water, grass, and/or ice type Pokemon.