After you make your way west through South Province (Area Two), you reach the town of Cortondo, home of the Bug-Type Gym.
In the back yard of the house just west of the Cortondo (East) Pokémon Center, there is a Super Potion.
Just east of the Cortondo Gym, there is an X Attack behind a wall.
North of the Cortondo Gym, you find Soapberry, and north of Soapberry, there are large trees. Check behind one of the big trees to find a Big Root.
One of the people on the main street the town, just west of the Cortondo Gym, will trade you a Snom if you trade away a Flabébé. Glen's Level 10 Snom is named Snowsalot, and its Tera Type is Ice.
In the southwest corner of the town, you will find a Guard Spec.
Behind the Cortondo Gym, you find a TM037 Draining Kiss.
If you are ready, you can enter the Cortondo Gym.