List of SM pokemon that are good or at least have a usable niche in OU, and are not tapus/UBs/legends:
>Toxapex>Mimikyu>Alola Marowak, Muk, and Ninetales>Primarina>Inciniroar (once HA is released, maybe)>Bewear>Pyukumuku (very niche)List of old pokemon that are viable due to buffs
>Pelipper>Torkoal>MantineThis is about all I can recall.
>>31032464Things don't get "placed" in OU, tiers are determined by usage. Primarina won't be OU, but it will be viable in OU.