Walkthrough
You will come out of the Galar Mine on Route 4, a small path that will lead straight to Turrfield where the first Pokemon Gym can be found. These fields are filled with loads of Wild Pokemon (including Pikachu), as well as a number of Trainers looking to battle.
Electrike (30%): Levels 14-16
Galarian Meowth (23%): Levels 14-16
Yamper (20%): Levels 14-16
Pumpkaboo (21%): Levels 14-16
Pikachu(Sword)/Eevee(Shield) (5%): Levels 14-16
Eevee(Sword)/Pikachu(Shield) (1%): Levels 14-16
Galarian Meowth (35%): Levels 13-15
Wooloo (25%): Levels 13-15
Milcery (20%): Levels 13-15
Joltik (10%): Levels 13-15
Cutiefly (5%): Levels 13-15
Budew (4%): Levels 13-15
Ferroseed (1%): Levels 13-15
Special Overworld:
Diglett: Level 17
Skwovet (100%): Levels 13-15
Fishing:
Magikarp (70%): Levels 13-15
Chewtle (20%): Levels 13-15
Goldeen (10%): Levels 13-15
Trainers
Pokemon Breeder Jaime: Level 14 Galarian Meowth, Level 14 Seedot, Level 15 Butterfree
Poke Kid Shane: Level 15 Pikachu
Pokemon Breeder Bradley: Level 15 Electrike, Level 15 Lotad
Poke Kid Mia: Level 15 Eevee
Poke Kid Rhys: Level 14 Joltik, Level 14 Grubbin
Poke Kid Sunny: Level 15 Milcery
Items
Energy Root: Hidden Near Box By Berry Tree
Paralyze Heal: Hidden Near Poke Kid Shane
Nest Balls: Near Poke Kid Shane
Rare Candy: Hidden By Southeastern Rock
Energy Powders: Hidden By Southeastern Box
Sharp Beak: Near Eastern Waters
Paralyze Heal: Hidden On Pillar By Poke Kid Mia
TM07: Near Poke Kid Rhys
Ether: Hidden By Northwest Rock In Southern Grasses
Cleanse Tag: Near Pillar In Southern Grasses
Repel: Hidden Near Western Wheelborrow
X Accuracies: Hidden By Box Near Poke Kid Sunny
Silver Powder: Near Northwestern Tree
Energy Root: Hidden In Northwestern Ground
Revival Herb: Hidden In Southwestern Area Of Northeastern Grasses
Cheri Berries: Berry Tree
Pecha Berries: Berry Tree
Oran Berries: Berry Tree
Leppa Berries: Berry Tree