Most banned books in history that I know of:
>Gnostic texts (Nag Hammadi and later works)
Barnstone's Gnostic Bible and "The Nag Hammadi Scriptures: The Revised and Updated Translation of Sacred Gnostic Texts Complete in One Volume " both contain all of these works. The former contains Nag Hammadi and later works (like the Cathars whose heresy was squashed in the Albigensian Crusade where many were persecuted and murdered by the Catholics for spreading the truth) but isn't complete in the Nag Hammadi, but it is friendlier to the reader while the latter is only Nag Hammadi, is more scholarly and is complete in every known Nag Hammadi work that's been uncovered since 1945. The Gnostic religious texts are the most banned books historically and the only reason we still have them is nothing short of divine intervention.

Funny enough, the canonical Bible still has some Gnostic "Freudian slips" to it (like 2 Corinthians 4:4). While no "Gnostic" reinterpretations of canonical scripture exist as far as I'm aware, but the Codex Sinaiticus and Codex Vaticanus were used by early Christians and some Gnostics, although no solid full English translation of those two that I know of that exist as a standalone in one work.
>the Library of Alexandria
Not so much a "banned book" (or collection of books, rather), however when Julius Caesar besieged Alexandria in 48 BC, combined with the decline of the Roman and Byzantine period, Theophilus' destruction of Pagan temples and the Muslim conquests (among others) it became lost (not to mentioned how they used Papyrus scripts to write the documents with, which doesn't age well), so as a result, these works became lost, but what does survive is works by scholars associated with the library or the Hellenistic period that came before or after its destruction (and these are as of now being actively cataloged by Harvard University in over 540 volumes, labeled Green or Red to denote if its Greek or Roman, with more works still underway, called the Loeb Classical Library).

Any more forbidden/lost knowledge?

Funny, I recently got the Nag Hammadi scriptures book. Literally feels like you have literal forbidden knowledge. Reading about the history of how these came to be and found should be a book altogether.

hmmm I recently got the book of Enoch as well but I was kind of disappointed. There were some cool parts but I felt like I was reading fan fiction, which ultimately it is. Can't lie, I might get the Barnes and Nobel edition, the cover looks amazing.

If anyone has more biblical lost knowledge books, let me know. (except for Jewish mystics stuff, that stuff I don't mess with)

>>24630916 (OP)
Read William Blake. Start with The Marriage of Heaven and Hell, ideally a reproduction of his original printing, not just the text. The number of parallels in his works with Gnostic writings is uncanny. Even more so when you consider virtually no information, certainly no source texts, would have been available to him during his life.

Probably late radically pagan platonist theology of the Athenian school: Proclus, Damascius, and Simplicius, which was banned by Justinian (while leaving the more moderate, semi-Christian Alexandrian school, comprised of figures like Olympiodorus, alone). They fled the Byzantine empire temporarily to Sasanid Persia but were permitted to return later. No one really knows what happened to Damascius and Simplicius afterwards, perhaps they went back to their hometowns or they left behind a platonist school in Harran in modern Iraq that could have been the conduit for much of late platonist texts to the Muslim world although I think most scholars are skeptical of that nowadays

>>24630916 (OP)
Is that newer edition of the Nag Hammadi better than the older one? I read somewhere that it was heavy on things like gender neutral language, is that done for political correctness or because the actual words used in the original were strictly gender-neutral?

gnosticsm is extremly overrated and false
Library of Alexandria was bad, but later sackings like the 1204 sacking of Constantinople or of Bagdad were argueably worse

>>24630916 (OP)
you will never learn about gnosticism by reading the nag hammadi library
it will just seem like gibberish when you read it
you are better off asking gemini about gnosticism

i like the gnostic groups that believed procreation was evil
cathars
bogomils
marcionites

there were also gnostic sects who were sexual degenerates because they thought they didn't have to obey moral codes

https://en.wikipedia.org/wiki/Carpocrates

>>24633507
>Carpocratians believed they themselves could transcend the material realm, and therefore were no longer bound by Mosaic law, which was based on the material powers, or by any other morality, which they held was mere human opinion. Irenaeus offers this belief as an explanation of their licentious behaviour.