Who is in mind?
The great prophets of old, this subject is made clear in the passage itself:
32 And what more should I say? For time would fail me to tell of
Gideon, Barak, Samson, Jephthah, of David and Samuel and the prophets—
(Hebrews 11:32, NRSV)
All of these people, while not authors of a Prophetic Book, are Prophets in that they were receivers of the Holy Spirit (ie Jephthah, Judges 11:29) and with coming upon of the Holy Spirit comes a certain Prophetic designation (ie Saul 1 Samuel 10:10-11). Our list of suffering saints follows this mention of "the prophets" and reads:
...the prophets— 33 who through faith conquered kingdoms, administered
justice... (Hebrews 11:32d-33a, NRSV)
Very clearly, all the people in our list down to verse 38 are contained within the overall title "prophets".
But can we be certain of this conclusion?
Upon further examination we see that this passage is explicitly speaking of Prophets who had a special connection with God, a revelatory connection such that they even knew of the coming of Jesus:
39 Yet all these, though they were commended for their faith, did not
receive what was promised, 40 since God had provided something better
so that they would not, apart from us, be made perfect. (Hebrews 11:39-40, NRSV)
All these people, whoever they are, are prior to the coming of Christ and are spoken of as living significantly before the life of Christ. Yet hoping in the coming of Christ. Now this isn't just an isolated claim or some literary device. All over the New Testament, people claim to have known of special revelations (not always recorded in Scripture) that Old Testament Prophets had which pointed to Jesus. The originator of this tradition, that certain Prophets saw the coming of Christ (in a vision or something) is none other than Jesus. Consider the words of Christ:
56 "Your ancestor Abraham rejoiced that he would see my day; he saw it
and was glad.” (John 8:56, NRSV)
In John, what follows Jesus' extraordinary claim is an attempt on His life. Jesus' claim to have been present when Abraham received this revelation (and to know of it) was not something that the Jews of the day took kindly too. And thus is not something we should look for within Jewish writings of the period.
This passage is not merely recounting hagiographical snippets of martyrs, but recounting the sufferings of prophets who held on to the testimony of the Word of God in the face of extreme opposition. That testimony was the testimony of Jesus. This idea that the prophets foresaw, in the Holy Spirit, the days of Christ (and that the Church had exclusive access to this knowledge over their Jewish contemporaries) is central to Early Christian claims:
18 "In this way God fulfilled what he had foretold through all the
prophets, that his Messiah would suffer..." 24 And all the prophets,
as many as have spoken, from Samuel and those after him, also
predicted these days. 25 You are the descendants of the prophets and
of the covenant that God gave to your ancestors, saying to Abraham,
‘And in your descendants all the families of the earth shall be
blessed.’ 26 When God raised up his servant, he sent him first to you,
to bless you by turning each of you from your wicked ways.” (Acts
3:18, 24-26, NRSV)
So we see this is not just an isolated list of suffering saints. But it is a fragment of a much larger theological tradition belonging to the early Church. Embedded in this recounting of the sufferings of holy men is this idea that Christians are inheritors with them, that the Christian is incorporated into the ranks of the suffering prophets. The people in this list, are not Maccabean Martyrs, they are specifically mighty men of faith who communed with the Holy Spirit. A Spirit that the early Church claimed Christians had access to, a Spirit that revealed knowledge.
Clearly said, this passage is part of a much broader claim that the Church inherits the legacy of the Prophets. This legacy has two parts, a legacy of faith in Christ (or "faith in what was promised" Hebrews 11:39) and an unjust suffering for that faith.
Now that we know who we are talking about, we can ask where we can find information on these people.
Where to look for Information
Based on this interpretation we can look in the Old Testament, and perhaps in Jewish Traditions to find information on the lives of the Prophets. Unfortunately there are no truly verifiable and authentic accounts of the lives of the Prophets of the Old Testament outside of the Old Testament. Therefore, we are left only with the canonical 22 books of the Hebrew Bible. Thankfully, many of these specific details we can tie to certain biblical texts, with that we return to the citations in question coming from Hebrews 11:
and refused their release, so that they might gain a better
Resembles Micaiah who chose to prophesy destruction on Ahab and face prison, 1 Kings 22.
Still others endured mocking and flogging, and even chains and
Resembles Jeremiah 20, 38 and the other sufferings of Jeremiah
They were stoned
Resembles Zechariah, 2 Chronicles 20:22-24, possible reference by Jesus in Matthew 23:35, gives weight to this identification.
they were sawed in two, they were put to death by the sword.
It is hard to say who this refers to, but the common identification with Isaiah is unlikely given the late date of the source, (The Ascension of Isaiah 5:14. This line we are completely in the dark about.
They went around in sheepskins and goatskins, destitute, oppressed,
and mistreated. The world was not worthy of them. They wandered in
deserts and mountains, and hid in caves and holes in the ground.
We can link these to Elijah and Elisha, though we don't have descriptions of them, because of the emulation of John the Baptist, see Luke 1:17, 1 Kings 19 etc.
Now though we can account for some of this list, we can't account for all of it. It should be clearly stated that the Old Testament Prophets are seen to have terminated with the time of Ezra and Nehemiah (given the chronology of the Book of Twelve and the closing of the Hebrew Canon). This Prophetic Tradition according to the New Testament resumes with John the Baptist who reveals the One whom all the Prophets of old spoke of, Jesus Christ. There is no reason to think that there are any references to Maccabees here or to any Apocryphal Literature, but what is probably in mind are some proto-Christian traditions that come directly from Jesus regarding prophetic continuity. Consider Luke 24:26-27, Acts 1:1-3, 1 Peter 1:10-12 and Mark 12:36, Matthew 22:43, Acts 1:16, Acts 4:25 and 2 Peter 1:21. These are our earliest sources on this tradition, a tradition which soon disappears and does not come up in the Church Fathers. It is a tradition with strong roots in the teachings of Jesus, consider Luke 20:9-18 and its parallels as a representative text of this tradition, as well as passages like Luke 11:49-51.
One of the hardest things in Biblical Studies is realizing how much the Bible leaves out, while hinting at (ie 1 Chronicles 29:29). It is wholly impossible to reconstruct the full knowledge and mind of someone we meet in regular day-to-day conversation, much more so someone who wrote a Book of the Bible almost 2000 years ago. But, what we can glean is that this author is not writing in isolation, he is part of a broader tradition seeing a unity between the Prophetic Tradition of the Hebrew Bible and that of the Church. Perhaps as he was writing this list he had in mind the suffering of Christian saints, people like St. Stephen, St. James and St. Paul, that paralleled the experiences of this Prophetic Tradition (and thus validated their place as successors of it).
Can we still find some of these traditions? And where did they come from?
Unlikely. It seems impossible to find this information today, some things are just lost in the sands of history. The Bible is our only potential witness to this broader tradition. Where did this knowledge come from? It's hard to guess, but we reasonably conclude that in the time of Christ there was knowledge on how Habakkuk, Obadiah, Zephaniah, Amos, Jonah etc. died. Among who knows what other variety of traditions and legends. Though these knowledges and traditions do not survive today, we see their fingers in the New Testament, perhaps a prophetic tradition on Elijah influenced the unique lifestyle of John the Baptist. Additionally, when you allow for the ecstatic/prophetic nature of the early Church (visions, dreams, divine revelations), who can limit their potential sources - not to mention their proximity to Jesus who could claim to even know the secret prophetic visions of Abraham (John 8:36).
In closing. From a textual perspective we see that the people in mind are the Old Testament Prophets who had a knowledge of the coming of Jesus and held fast to those promises. This is a unifying theme in the New Testament, that the Church inherits the authoritative Jewish Prophetic Tradition that Jesus was the fulfillment of. Who specifically is in mind in these verses is unknown, simply that they were "prophets". We have some hints in the Old Testament, but not much. We must humbly admit the author would have had access to information that we cannot even speculate as to its full content and scope, we can debate all we want, but we can hardly verify with certainty our conclusions.
I hope that answers your question. Take care and God bless.