>>51256472One Pokemon OR a trailer that showcases competitive elements (we haven't seen anything pertaining to this yet)
The most likely new Pokemon they would show would be an evolution of Pokemon we all know. Primeape, Dunsparce or Girafarig.
They're not going to introduce the paradox pokemon concept.
They might show mushroom tentacruel or eel diglett, but I don't think they will since they're likely version exclusives and they wouldn't be inclined to show one half of a version exclusive pair.