What documents in the New Testament do you think are forged, as opposed to being written by different authors of the same name? To my knowledge, aside from controversial works of higher criticism that suggest that several Pauline epistles were not written by St. Paul, which are not widely accepted by most Christian theologians, the only text widely regarded as spurious to the point where several recent Bible translations omit it is the Longer Ending of Mark. There is also the case of the Adultery Pericope, which appears to be an interpolation, but that does not mean it is not an authentic text.
In the early church, as you doubtless know, the authenticity of the Apocalypse, James, Jude, Hebrews and 2 Peter was doubted, and these were not included in the original Peshitta, but were later added to the Western Peshitto used by the Syriac Orthodox, Maronite Catholics and various smaller churches of the same liturgical rite from the 6th century Harklean Bible translated by St. Thomas Harqel.
Also out of curiosity are there any works you think should be in the canonical New Testament which are rejected as Apocrypha?