14level cap
Brock fields 3 Pokémon between level 12 and level 14 in Pewter City Gym.
This is around Pallet Town to Pewter City — Lv. 14 cap in the story — that page lists everything you can have caught by this point.
Types on this team: Rock ×3Ground ×2Water
| Pokémon | Ability & item | Moves | Base stats | |
|---|---|---|---|---|
 | Geodude Lv 12 RockGround | Ability Rock Head | Block Defense Curl Rock Tomb Tackle | HP40Attack80Defense100Sp. Atk30Sp. Def30Speed20Total300 |
 | Onix Lv 14 RockGround | Ability Rock Head Held item Oran Berry | Dragon Breath Torment Rock Tomb Bind | HP75Attack80Defense160Sp. Atk40Sp. Def65Speed90Total510 |
 | Kabuto Lv 13 RockWater | Ability Swift Swim Hasty nature | Rock Throw Absorb Scratch | HP30Attack80Defense90Sp. Atk55Sp. Def45Speed55Total355 |
How to beat this team
Shared weaknesses. Fighting hits 3 of 3, Grass hits 3 of 3, Ground hits 3 of 3, Ice hits 2 of 3.
Level to be ready for. Lv 14 — Onix, the highest on the team.
Fighting Pokémon you can have caught by this point. From this guide’s own encounter tables, by Pallet Town to Pewter City — Lv. 14 cap:
- Mankey — Route 22, Lv 3