Pokemon Found Everywhere
Pokemon Found During Horde Battles
Once you head inside, head west from the entrance. You'll eventually come upon a trainer.
Trainer Battle: Pokemon Breeder Mercy
Heading further west up the stairs and then south will reveal that you can't proceed any further from this entrance until you gain the ability to use Strength . Until then, we may as well head back outside.
Back outside, you'll notice another Photo Spot which you can make use of, so feel free to. Once you're done; head south until you see stairs leading west. Go up them and continue following the path until you see tall grass to your south. Head into it and head west through it.
You'll eventually reach a Persim Berry tree that you can collect a berry from. You'll also be able to find a Tiny Mushroom just south of the tree. Head back to the path and continue on. You'll find a spot where a tree can be Cut, so make sure to do that. Follow the path that just opened up and you'll find a Silver Powder at the end.
Head back, then west through another entrance into Connecting Cave - Zubat Roost. Now that you're back inside the cave; head west. When you reach a scientist; talk with her and she'll heal your Pokémon. Continue on through and out. You'll appear in Route 8.
Tip #015: Warning About HMs
HMs are useful for clearing field obstacles, but watch out that you can't overwrite them if your Pokémon learns a new move. Well, not until you meet the Move Deleter later on. As such, be sure you really want them on your Pokémon; if necessary, you can appoint a "HM slave" who carries all your HMs, freeing up your battling Pokémon's moves.