A total of 9 or 10 guys are credited with writing the New Testament. These include the apostles John, Levi Matthew, Paul and Peter. There was James, who was the brother (or half-brother) of Jesus.
There was Luke, who is said to have been Paul's physician. There was Timothy, an associate of Paul. There was John Mark, an associate of Peter.
There was Jude, who identified himself as the brother of James. If the James he was talking about was the brother of Jesus, then that would make Jude (or Judas) also the brother of Jesus (see Matthew 13:55, Mark 6:3 and John 7:5).
It is not clear who wrote the Book of Hebrews, although some believe it may have been Paul.