What are the 12 themes of the bible?

First off, there are a lot of themes within The Bible. I think it's good to realize that each "book" was written separately by different groups of people. As such, the books of the Bible often have interlocking themes, but each book addresses one or more themes. Many books, like Jude or most of the New Testament writings, introduce themes as well in an effort to address more confusing ones.

Also, while Theological and Secularly developed themes are slightly different, they are also intertwined. A new Secular discovery will spur a Theological research effort, and vice versa.

It also depends on what you want answered. Some people would call marriage a "theme," when really it is probably a part of the theme, "New Testament adjustment to Mosaic Law."

Anyway... common themes include Cosmogony, or creation stories, (from three different documents in the Old Testament, as well as in Jude and numerous places in the New Testament).

Post-Exodus rituals. This is after Levitic Law and includes the Passover, which is a large part of this theme. It expands on the symbolic meaning of actions, especially remembrance and ancestry.

Ancestry and Old Testament concepts of the Messiah.

New Testament concepts of the Messiah.

There are many more, but these are some that span the entire Bible. And also what I can think of just off the top of my head.