Celadon City

Walkthrough
Celadon City is a massive city with loads of attractions. Firstly, it's home to the fourth Pokemon Gym. The city even has a Game Corner to play in and a Department Store with tons of items to purchase. You will need HM Cut to challenge the Celadon City Gym, but since you already have it in your arsenal, you can battle it immediately after arriving. You have a few goals before leaving Celadon City and heading back to Lavender Town: defeat the Celadon City Gym, defeat Team Rocket in their Hideout below the Game Corner, and obtain the Tea (which will help you get into Saffron City) from the Elderly Lady in the Celadon Mansion.

Move Tutors
Counter: Tutor Can Be Found On The 3rd Floor Of Department Store
Softboiled: Tutor Can Be Found On Opposite Side Of Water

Gift Pokemon
Eevee: Can Be Obtained At The Top Celadon Mansion (Secret Back Entrance)

Wild Pokemon
Surfing:
Psyduck(FireRed)/Slowpoke(LeafGreen) (99%): Levels 5-40
Koffing (1%): Levels 30-40

Old Rod:
Magikarp (100%): Level 5

Good Rod:
Magikarp (100%): Levels 5-15

Super Rod:
Magikarp (99%): Levels 15-35
Grimer (1%): Levels 30-40

Items
PP Up: ItemFinder
Tea: From Elderly Lady In Celadon Mansion

Department Store Items
2nd Floor - Counter 1:
Great Ball, Super Potion, Revive, Antidote, Paralyze Heal
Awakening, Burn Heal, Ice Heal, Super Repel

2nd Floor - Counter 2:
TM05, TM15, TM28, TM31, TM43, TM45

4th Floor:
PokeDoll, Retro Mail, Fire Stone, Thunderstone, Water Stone, Water Stone

5th Floor - Counter 1:
HP Up, Protein, Iron, Calcium, Zinc, Carbos

5th Floor - Counter 2:
X Attack, X Defend, X Speed, X Special, X Accuracy
Guard Spec, Dire Hit

Rooftop:
Fresh Water, Soda Pop, Lemonade