The Shadow Pokemon
A spooky but friendly species that exists entirely in the second dimension, Umbruh attaches itself to other Pokemon's shadows to move around.
The Follower Pokemon
Shadood is a friendly Pokemon that can communicate with other creatures' shadows. These shadows find Shadood's chatter annoying, though.
The Dark Blob Pokemon
Phenombra feasts on light. It is an outgoing Pokemon, but don't pet it! Its body is so cold, you may never be able to use your hand again.