I have not read through all of the replies but thought you might find something useful
HERE
I think I understand a bit of your frustration with trying to determine what Exactly comprises “Sacred Tradition” as opposed to “regular traditions”.
Let me place my 2c before you.
In so far as written items that would comprise Sacred Tradition I would say that any texts written by Church leaders before the time of the codification of the Bible would be a part of it. Even some of those documents considered and rejected for inclusion in the Bible can contain certain good elements and can be of help to the magisterium in discerning Truth and avoiding error.
Additionally the writings and letters of the various early Bishops and Saints contain a great deal of information on how the early Church believed and evolved and grew.
The last of the Written parts would be any and all of the documents from the various synods and councils.
These can all be considered as a part of the Deposit of faith upon which our Traditions rest.
As to the unwritten portion of Sacred Tradition, that is much more difficult pin down. Suffice it to say that the oldest and most important of these traditons would be the Church’s reliance on the Guidance of the Holy Spirit and the acceptance of a unified and authoritative Church. For both of these things must predate the written words of the NT and continue on today.
Peace
James