Walkthrough
On the other side of Underground Path 7-8, you will find Route 7. This path is much shorter than Route 8, but it does contain a number of Wild Pokemon Pokemon and a couple of Trainers. Route 7 will bring you to Celadon City, the same location where the Rocket Hideout can be found.
Wild Pokemon
Grasses:
Vulpix (19%): Levels 22-27
Pidgey (15%): Levels 22-27
Pidgeotto (15%): Levels 22-27
Rattata (15%): Levels 22-27
Raticate (15%): Levels 22-27
Jigglypuff (15%): Levels 22-27
Abra (4%): Levels 22-27
Ninetales (1%): Levels 22-27
Kadabra (1%): Levels 22-27
Grasses - Special Spawns:
Porygon: Levels 22-27
Sky:
Pidgey (60%): Levels 3-56
Pidgeotto (35%): Levels 3-56
Pidgeot (35%): Levels 3-56
Sky - Special Spawns:
Dragonite: Levels 3-56
Charizard: Levels 3-56
Articuno: Levels 3-56
Zapdos: Levels 3-56
Moltres: Levels 3-56
Trainers
Ace Trainer Yvette: Level 28 Raichu, Level 29 Dugtrio, Level 28 Seel
Coach Trainer Alpesh: Level 29 Farfetch'd, Level 30 Wigglytuff
Obtainable Items
Elixir: Near Saffron City Gate
Ultra Balls: Defeat Ace Trainer Yvette
TM12: Defeat Coach Trainer Alpesh
Post Game
Walkthrough
After defeating the Elite Four and starting the Master Trainers Challenge, you will find a couple of Master Trainers on Route 7. In total, there will be two Master Trainers to defeat.
Trainers
Hiker Benjamin (Master Trainer): Level 75 Sandslash
Ace Trainer Austin (Master Trainer): Level 70 Growlithe