Ultrabeast Fallers
(Does not have to be based on a cannon Ultra Beast. If you would like to design an Ultra Beast for the fake-dex see the guide for submitting fakemon, it would be very welcome)
Aliens.
Out right not from a world anything like our own. Nothing makes sense. Nothing fits.
You can also use this as an excuse for “fantasy races” such as Orcs, Elves, etc.