Oceanus

According to Homer and Apollonius of Rhodes, Oceanus wasn't a Titan like in Hesiod's Theogony. Rather, he was primeval Ocean. See also the Titans, Oceanus.

According to Homer, the gods arose from Oceanus and Tethys. Like Hesiod, the river Ocean (or Oceanus) surrounded the flat disk of the Earth (Gaea). The river Oceanus was the outer limit of the universe where the sun didn't shine. See Homeric Creation.

According to Apollonius, Oceanus was possibly the father of the Creator Goddess Eurynome. Either Eurynome self-created herself by springing out of the Ocean, or he actually fathered her. See also Eurynome and Ophion in the Creation page.

The historian, Diodorus Siculus, wrote:

For I go to see the ends of the bountiful earth,
Oceanus source of the gods and Tethys divine
Their mother.

Though there are no actual myths about Oceanus being a Creator god other than brief references scattered throughout the ancient sources, so we can only guess of his importance in the Creation myths.