Quoted By:
Maractus and Cacturne are definitely not safe. Pretty much anything that hasn't appeared since gen 5 bar remakes isn't safe. Except for Seismitoad, since that's already confirmed.
I thought all of gen 1 was safe because of LGPE, but somehow I expect them to find a way of not putting Venomoth or the Hitmons in the game yet keep fucking Psyduck and Goldeen (we already know worthless Goldeen is in as well). They seem to reuse the same mons over and over again, not just gen 1 stuff either, but things like Pelipper and Flygon.