old testament: a
jahwist source(Yahweh worship),
Elohist(worshipped the babylonian gods elohim and their chief god El, and since then El has become synonymous with YHWH),
and Deuteronomist source,
with alot of overlapping all over the place and writing in the name of "moses" and "david" and so on.
and for the gospels, random Christians many years after Jesus, writing gospels anonymously, with names later assigned by church history; the religious assume that the disciples lived very, very long lives and wrote them years after the fact.
otherwise, it's assumed that they are copied and edited out of an original "q" source that noone has ever found.