Question:
Answer:
Probably nothing. The most ancient view is that everything contained in Tradition is in some sense to be found in Sacred Scripture. Later, in reaction to Protestant errors about Tradition, some theologians began to say that there are some things that are found in Tradition and not in Scripture at all. Catholics are allowed to hold different views on the question as long as they hold that the revelation of Christ is to be found in both Sacred Scripture and in Sacred Tradition.
The relationship between the two is a matter of discussion. St. Thomas Aquinas is of the opinion that all revealed truths are contained in Sacred Scripture. This is not the same as the sola scriptura doctrine of the Protestants; he simply asserts that whatever the authority of the Fathers and Doctors and Magisterium teach is also to be found in God’s word. Read the Dogmatic Constitution on Divine Revelation of the Second Vatican Council, and you will see the teaching serenely presented.
There is, however, one teaching that must be from Tradition alone, and it is the foundation of our acceptance of Sacred Scripture. This is the teaching on the canon of Sacred Scripture, namely, which books are divinely inspired. How do we know which books of the Bible are inspired? Not from the books themselves, surely, but from Tradition.
The whole New Testament from Matthew to the book of Revelation contains no list of the books that make up the New Testament. This was established by the Tradition of the Catholic Church. The same goes for the Old Testament, from which the Jews and Protestants removed books because they were not originally written in Hebrew: how do they know that the others are inspired, say the first five books, the Torah, or the prophets or psalms? This can only come from Tradition.
So the short answer is: Everything is in Scripture except the canon of Scripture itself. Remember, the Church existed for more than a century before the New Testament was put into one collection. During that time it was Sacred Tradition that guided the Church, coming from the same apostles who largely wrote the New Testament. That being said, everything they taught that is meant to be an article of faith is in some sense in the Bible.