Most, if not all, of the Gospels were written before 100 AD, iirc.
ALL 4 gospels are referred to before 100 AD, which tells us that all 4 that we refer to, were written before 100 AD
The Synoptic gospels date to before the destruction of the 2nd temple.
The Gospel as per John was written later - probably the late 80s AD, but still before the end of the century.
The Gnostic “gospels” mostly date to the 2nd or 3rd centuries - 200 to 300 years after the Crucifixion