The Didache is an anonymous non-cannonical text that may predate all of the connonical gospels. It is heavily debated whether it's actually written by the Apostles or not.
The Gospel of Thomas is a Gospel that wasn't included in the Bible. This text was originally written in Greek, but the only complete version was translated to Coptic. This work was found in the Nag Hammadi Library, and translated into English.