Of all the lost texts, the one I'd like to read most is Porphyry's "Against the Christians". It was a massive 15 volume work refuting every aspect of Christianity from both a historical and philosophical standpoint, he even had access to sources we don't have anymore like histories of the Phoenicians (he was from Tyre himself). It's arguments were so searing that multiple Christian emperors had it banned. Even mentioning the arguments he used was banned, so Christians' attempts at "refuting" it didn't survive either. We only have a few fragments via quotations, and even from what little we know, a lot of it has been independently proven to be correct (for instance, he brought up that the Book of Daniel was NOT written during the Babylonian exile but rather, it was written in the 180s BC under the reign of Seleucid king Antiochus IV Epiphanes).
>>17812247 (OP)
Also celsus
Also celsus