British Celtic Pantheon
A somewhat hypothetical goddess, based on the name of the river Aeron in Cardiganshire, which means "slaughter"--Welsh aer. In early British, this would be rendered *agro-, and as most river deities in the Celtic pantheon are goddesses, it is assumed that this would also have been a goddess.
If this Argona did in fact exist in the British pantheon, then she would have been a cognate of the Irish goddess Morrígan, the goddess of battle and slaughter. Morrígan, however, was not a river goddess, though one of Morrígan's triplets, Macha, was goddess of Emain Macha, the seat of the kings of Ulster. If so, Agrona would have been part of the cult of the Mothers--the triple goddesses of war, magic, and prophecy.