The Pharisees and the Sadducees may not be given enough recognition in the Bible but it should be remembered that these two also have with their own differences. The Pharisees believe that God provided the Jews with written laws but also provided the Jews with oral laws that should be followed at all time.
The Sadducees believe that there are other texts and laws that are outside from Torah that people may be following but they themselves, they believe that these texts and laws should not be a part of their law. Take note that these two are a couple of the big religious movements during that time along with the Essenes.