Walkthrough
Since you won't be able to proceed to the Seventh Floor of the Pokemon Tower without the Silph Scope, you will need to pursue Jessie & James by heading west of Lavender Town on Route 8. This path is full of even more Wild Pokemon to catch, as well as tons of Trainers to battle. Route 8 leads straight to Saffron City; however, since you won't have access to that city just yet, you will have to use Underground Path 7-8 to reach Route 7 instead.
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:
Chansey: 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
Beauty Aubrey: Level 26 Clefairy
Gamer Rich: Level 35 Seaking
Super Nerd Aidan: Level 27 Koffing
Rocker Glenn: Level 27 Jolteon
Ace Trainer Kyla: Level 28 Kadabra, Level 29 Machoke
Gamer Stan: Level 35 Rhyhorn
Lass Andrea: Level 25 Meowth, Level 25 Meowth, Level 25 Meowth
Lass Megan: Level 25 Pikachu
Super Nerd Leslie: Level 27 Magnemite
Obtainable Items
Poke Balls: Defeat Beauty Aubrey
Poke Balls: Defeat Gamer Rich
Poke Balls: Defeat Super Nerd Aidan
X Speed: Near Super Nerd Aidan
Poke Balls: Defeat Rocker Glenn
Fire Stone: Middle Grass Area (Requires Chop Down)
Ultra Balls: Defeat Ace Trainer Kyla
Poke Balls: Defeat Gamer Stan
Big Mushroom: Beneath Ledge Near Underground Path
Poke Balls: Defeat Lass Andrea
Poke Balls: Defeat Lass Megan
Poke Balls: Defeat Super Nerd Leslie
Post Game
Walkthrough
After defeating the Elite Four and starting the Master Trainers Challenge, you will find a couple of Master Trainers on Route 8. In total, there will be two Master Trainers to defeat.
Trainers
Bug Catcher Terry (Master Trainer): Level 75 Beedrill
Hiker Richter (Master Trainer): Level 70 Cubone