Interactable Pokémon

After you have defeated Team Galactic in the Valley Windworks, the Windworks manager will say that the Pokémon that appears may start appearing again. From the following Friday and every Friday afterwards, you will now find Drifloon floating outside the Valley Windworks.

Drifloon Level 22

OT: Yours ID: Yours Ability: Aftermath or Unburden

??? Nature. Date of Receiving Valley Windworks. Level Met: 22

Focus Energy Payback Hex Shadow Ball

If you find an Odd Keystone, either through the Grand Underground or otherwise, you can place it in the mysterious cumbled Hallowed Tower in Route 209. From there, if you interact with NPCs in the Grand Underground, it will build the energy to unleash Spiritomb. You need to have interacted with 32 different people in order to get Spiritomb. When you interact with the Hallowed Tower before then, you will get a message which can indicate how close you are

Click here for details on Underground NPCs

Spiritomb Level 25

OT: Yours ID: Yours Ability: Pressure

??? Nature. Date of Receiving Route 209. Level Met: 25

Spite Payback Nasty Plot Hex

After you have the National Pokédex, if you go to the Old Chateau, if you go to it at night and interact with the TV in one of the rooms on the second floor, you will be able to get the Pokémon Rotom. Once defeated, you'll receive the Secret Key which you can take to the Eterna Galactic Building to change Rotom's form, getting the Rotom Catalogue when you enter the first form, and being able to change form to whichever you have had Rotom enter

Rotom Level 15

OT: Yours ID: Yours Ability: Levitate

??? Nature. Date of Receiving Old Chateau. Level Met: 15

Double Team Thunder Shock Confuse Ray Charge