Other christian denominations are tiny minorities in Poland, i can think of two other catholic ones out the top of my head, Polish-catholic and Greco-catholic but those are just like tiny local gangs compared to central mafia. Maybe even worse since Greco-catholic is use as wedge against Ukraine and Russia by the pope, and Polish-catholics are wacko sect which only beef with r-c they had is that for them r-c is way too progressive.