What Pokemon still cannot pass down ball (other than pokeball) when breeding in Pokemon Omega Ruby?
Example: Female Froakie can be captured in Pokemon Y, so it can pass different type of balls.
All females can pass down the Pokeball sprite when bred with another Pokemon that is not Ditto. However, when bred with a Ditto, the Pokebal sprite will not pass down.
Source: Question like this before and experience
EDIT: List of Pokemon that cannot be caught but only obtained and cannot breed to pass down the Pokeball:
None. Except Jhoto starters and Sinnoh Starters and Unova starters starters.
Hope I helped!
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