Strategies
16 published write-ups for Pokemon Yellow.
Battle
Beating Brock
Geodude L10 and Onix L12 - and your starter Pikachu cannot touch either of them.
Beating Misty
Staryu L18 and Starmie L21. Finally, a gym Pikachu was built for.
Beating Lt. Surge
One Raichu at level 28 - but first you have to get through the door.
Beating Erika
Tangela L30, Weepinbell L32 and Gloom L32 - two of them double-weak to Fire.
Beating Koga
Venonat L44, Venonat L46, Venonat L48 and Venomoth L50 - a wall of sleep powder.
Beating Sabrina
Abra L50, Kadabra L50 and Alakazam L50 - and Generation I has no answer to Psychic.
Beating Blaine
Ninetales L48, Rapidash L50 and Arcanine L54 - bring water.
Beating Giovanni
Dugtrio L50, Persian L53, Nidoqueen L53, Nidoking L55 and Rhydon L55.
Elite Four: Lorelei
Dewgong L54, Cloyster L53, Slowbro L54, Jynx L56, Lapras L56.
Elite Four: Bruno
Onix L53, Hitmonchan L55, Hitmonlee L55, Onix L56, Machamp L58.
Elite Four: Agatha
Gengar L56, Golbat L56, Haunter L55, Arbok L58, Gengar L60.
Elite Four: Lance
Gyarados L58, Dragonair L56, Dragonair L56, Aerodactyl L60, Dragonite L62.
Champion: Blue (all three Eevee variants)
Six Pokemon at L59 to L65, and which six depends on a battle you fought in the first hour of the game.