i believe if there was anything extra that we needed God would have put it there
Constantine help put the bible together and decided which scrolls needs to be in the bible i think or was it Martin Luther? (with the help of God ofcz). It's believed that he wanted unity among the people, but don't know much about that.
Anyway the roman catholic should have the same bible otherwise they have put some of the extra 'dead sea scrolls' in their bible for instance 'The book of Enoch'
We trust though that everything in our bible is more than enough as long as the information is not falsified. But like i said their are plenty of lost books that are not included in our bible.
Some of the books i found on the internet that are not in the bible,
THE EPISTLE OF BARNABAS
THE BOOK OF JASHER
THE REPORT OF THE PONTIUS TO TIBERIUS
LETTER OF HEROD TO PILATE TO HEROD
THE DEATH OF PILATE THE GOVERNAR
THE TRIAL AND CONDEMNATION OF PILATE
THE GOSPEL OF NICODEMUS
THE EPISTLE OF PONYIUS PILATE
THE GOSPEL OF THE BIRTH OF MARY
THE PROTEVANGELION
THE ACTS OF PAUL AND THECLA
THE FIRST GOSPEL OF THE INFANCY OF JESUS CHRIST
THOMAS 'GOSPEL OF THE INFANCY OF JESUS CHRIST
THE LOST GOSPEL ACCORDING TO PETER
THE SHEPARD OF HERMA
EPISTLES OF CLEMENT TO THE CORINTHINAS
THE BOOKS OF ADAM AND EVE
THE BOOK OF THE SECRETS OF ENOCH
THE TESTAMENTS OF THE TWELF PATRIARCHS
THE GENERAL EPISTLE OF BARNABAS
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i do not know HOW true they are though. To be honest i only really trust the books that in the bible.
We have to trust the words in the bible as it is the written Word of God (we believe this to be 100% true)
2 Timothy 3:16
All Scripture is God-breathed and is useful for teaching, rebuking,
correcting and training in righteousness.
Think about it if we had to have all these books in our bible it would have been a 100 000 pages long at least