Like the Mormons, the Catholics have plenty of extra biblical works including the Catechism, papal authority, tradition, and scavengers of history. Mormons and the Restored Church say they have apostolic authority as does the New Apostolic Reformation which claim theirs began anew in 2002.
Christian Science with Key to the SCRIPTURES backs up the Bible for those of the Christian Science Faith. Cults all seem to need something plus the Bible. My church uses the Bible alone. For example, examine the scavenger of history Catholics. Their Faith didn’t begin whole in the first century but mine did. In fact the gospel was only in the mind of Jesus until He revealed it to Paul by way of Revelation. In truth, the Apostle Paul began the church movement not Peter. Peter received the keys to stand outside the gates of heaven. Did he ever get in?
The Catholics claim to be the oldest church so if they like numbers Paul wrote 13 books to the 2 books that Peter wrote. Who had the pen of a ready writer? Maybe the Catholics ought to be studying Paul more than Peter and the four verses Mary spoke?