Ash tries to catch a Mankey in 'Primape goes bananas' but inadvertently snares a rice ball.
The Poké Ball appears to successfully digitise it, but then rejects it immediately afterwards.
Mewtwo's special balls in 'Mewtwo Strikes Back' are capable of capturing Poké Balls, complete with their cargo of Pokémon.
As can be seen in 'The Tower of Terror', you can't catch a human with a standard ball.
However, the Pokéstar Studios movie Timegate Traveler is about a future where Bug-type Pokémon now rule the world and keep humans in specially designed Human Balls.