What Bible did the Bible characters read?

David, Samson and Ezekiel unquestionably read the Torah, which was from the time of Moses, many years before Samson. Later came David, who wrote some of the Psalms, so those were available to Ezekiel, who was quite a while after David.

Ezekiel would thus have had the histories of the kingdoms of Israel and Judah -- 1 & 2 Samuel, 1 & 2 Kings, 1 & 2 Chronicles (alternately called 1-4 Kingdoms and 1 & 2 Chronicles.) Isaiah would also have had every these same books.The people of Israel wrote their histories as they went along.

The oldest-known proto-Bible dates to the early fourth century C.E.

That is: centuries after the last of the Biblical documents were authored.

Before that time

what was available were inexpensive codices

and (more typically) scrolls

typically of individual documents.

(E.g. The Book of Genesis would be on one scroll, The Book of Exodus on another scroll.)

One might collect such scrolls, forming a collection or "library" similar in content to the Bible...

but it wasn't a book. It was a collection of documents, and there were no rules regarding what documents should and should not be collected by Christians

or by the ancient Jewish people that you mention.

Noah and Enoch - had to exist before the first Biblical book existed.

David and Samson - if we accept the Biblical account and/or linguistic analysis, existed before Torah existed, but they would have had part of Torah. For example: perhaps they had Genesis and Exodus. Probably these documents were, in their time, quite different from what they are today. David should also have had access to the source documents and/or stories that later were used to produce Judges, and of course Ruth would have been a family story for David. Also: David himself was author of most of the psalms.

Daniel, Ezekiel and Isaiah should have had Torah, and it probably would have been pretty similar to what we have today. They would also have had Judges and Ruth at least in oral form. They probably had access to the documents that were later used as sources to produce Samuel, Kings and Chronicles.

THEY READ FROM THE TORAH SCROLLS AND OTHER SCROLLS OF PROPHETS AND PSALMS.

WHEN NOAH WAS ALIVE THERE WERE NO SCROLLS, HE HAD A RELATIONSHIP WITH YHVH GOD.

The fact of the matter: They read what is the Torah the Hebrew bible.

What Bible did the people in the Bible read.

Imaginary, every one.  Oh yeah, baby!

I don't recall any scripture saying. But, Daniel was from the royal family, so he was educated. Ezekiel & Isaiah were Judges & priests. Part of their duties were to read God's word aloud to the people. Noah & Enoch did not leave any of their own writing, so we do not know.

They had Divine Inspiration, the prophets and the priests.

ahem  Noah and Enoch had the what was told them

Everyone else rad the Pentetuch

David didn't read anything. That's what Samuel was for.