A good idea for a topic.....I have grave doubts that the numerous volumes attributed to Papias (along with Hegesippus) ever existed. I suspect the references to Papias are later inventions and back-interpolations. So I naturally wouldn't pick Papias. The others seem like good ideas, but I honestly doubt another Pauline letter would tell us much we didn't already know.
- Papias' five-volume "Expositions of the Logia of the Lord,"
- The whole "Gospel of Peter," due to its significance in some prominent historical Jesus research.
- A whole copy of an early Greek manuscript for the "Gospel of Thomas," for the same reasons as the "Gospel of Peter."
- The "Gospel of the Nazareans" and the "Gospel of the Hebrews," as there are many intriguing questions related to these and the canonical Gospels, especially Matthew. And while we're on these, I'll throw in the "Matthew Logia" mentioned by Papias, if it was something different from canonical Matthew.
- The lost letters of Paul, his "Letter to the Laodiceans," or even more, his lost letters to the Corinthians, his initial letter on sexual immorality and his "difficult letter." And, while we're at it, I'll throw in the Corinthian letter to Paul which, in part, occasioned 1 Corinthians.
I don't believe in Q and I think Thomas depends on Mark, so my own list would be:
[Christianity] [historical Jesus] [Gospel of Mark]
- The whole Gospel of Peter. Very important for seeing how the Jesus story evolved -- my friend Neil Godfrey has recently used it in conjunction with Justin Martyr to argue for a pre-Mark Passion.
- An uninterpolated copy of Josephus Wars, Antiquities, and Vita. I suspect that there has been widespread tampering, not merely in the two Jesus references.
- Complete texts of more Greek novels currently existing only in fragmentary form, such as Ninus.. I believe they were critical for the development of the Gospel of Mark and Acts, among others.
- A complete copy of the writings of Justus of Tiberias.
- A copy of the Gospel of Mark prior to the redactions in which the original ending was removed and Bethsaida interpolated and re-arranged -- just because I love Mark.