Here is a list of mythical creatures beginning with this letter and I am constantly gathering information from each continent and continually updating.
Argus Panoptes (Greek)
Argus Panoptes was a giant of Argolis in the Peloponnese. and the guardian of the heifer-nymph Io and the son of Arestor. According to Asclepiades, Argus Panoptes was a son of Inachus, and according to Cercops he was a son of Argus and Ismene, daughter of Asopus. Acusilaus says that he was earth-born from Gaia.
He had immense strength, but what set him apart was the fact that he was adorned with a hundred seeing eyes. The eyes were either spread across his body, or simply found upon his gigantic head. As a result of having so many eyes, Argus Panoptes was said to be always awake for only two eyes went to sleep at one time, ensuring that 98 eyes were always functioning.