What was the most important of the roman assemblies, in which plebeians outnumbered patricians?

This was the tribal assembly. This body of government was represented by all the citizens of Rome, who were placed in one of 35 tribes, based upon where the citizen lived. This assembly voted, by tribe, on all matters to do with the Roman government. Once a decision reached a majority of the tribes, it was considered decided. Plebeians outnumbered patricians because this was an assembly made up of all of the citizens, not just an elected few.