There were basically 3 important Jewish sects at the time of Jesus:

1) Pharisees
2) Sadducees
3) Essenes

Now, the Pharisees..of them we read a lot of in the Bible. Modern Rabbinic-Talmudic Judaism was formed from a Pharisees origin. The Pharisees developed into Talmudic Judaism eventually that we know today, after the destruction of the Temple in Jerusalem in 70 AD.

The Sadducees had odd beliefs..they didn't believe in spiritual things and were like the atheists of their day.

The Essenes...kept to the Law and Prophets, and did not regard tradition as superior to scripture, as was the habit of the Pharisees.

The Essenes were very messianic in outlook, and noticed by studying all the writings of the prophets and patriarchs that the coming of the promised Messiah was imminent. John the Baptist is said to have been an Essene.

It appears that the Essenes accepted Christianity en masse, and became known as Christians and indistinguishable from other Christians eventually. So they disappear as a group from history.