Here are some good reference works in which you can find in-depth answers to your questions about books that were excluded from the canon, the dates they were found, reasons for their exclusion, etc.

• The Gospel of the Birth of Mary

• The Protevangelion

• The Gospel of the Infancy of Jesus Christ

• The Infancy Gospel of Thomas

• The Epistles of Jesus Christ and Abgarus King of Edessa

• The Gospel of Nicodemus (Acts of Pilate)

• The Apostles' Creed (throughout history)

• The Epistle of Paul the Apostle to the Laodiceans

• The Epistles of Paul the Apostle to Seneca, with Seneca's to Paul

• The Acts of Paul and Thecla

• The Epistles of Clement (The First and Second Epistles of Clement to the Corinthians)

• The Epistle of Barnabas

• The Epistle of Ignatius to the Ephesians

• The Epistle of Ignatius to the Magnesians

• The Epistle of Ignatius to the Trallians

• The Epistle of Ignatius to the Romans

• The Epistle of Ignatius to the Philadelphians

• The Epistle of Ignatius to the Smyrneans

• The Epistle of Ignatius to Polycarp

• The Shepherd of Hermas (Visions, Commands, and Similitudes)

• Letter of Herod To Pilate the Governor

• Letter of Pilate to Herod

• The Lost Gospel of Peter

• The Epistle of Polycarp to the Philippians

• The Conflict of Adam and Eve with Satan (The First and Second Book of Adam and Eve)

• The Secrets of Enoch

• The Psalms of Solomon

• The Odes of Solomon

• The Letter of Aristeas

• The Fourth Book of Maccabees

• The Story of Ahikar

• Testaments of the Twelve Patriarchs

A search of the reference section of your local public library may well show these books on hand or available as well as quite a few others that will help you find the answers to your questions.

After some forty years of researching the subject and reading most of the "lost" books and apocryphal writing, I have never found one that an in-depth reading will not be self-explanatory as to why it was excluded from the canon.