I was reading a bit online about goddesses (which I see as archetypal, a way of understanding facets of the Divine, a way for us to feel connected to the Great Mystery.) One of the ones that stood out for me is actually one that doesn't seem to be as written about as some others, and that is the Celtic Goddess Danu. (Also known by other names, such as Anu, and Don in Welsh.) She is Ireland's Great Mother Goddess, married to the Sun God Belenos,an Earth Goddess, and who in some versions gave birth to Brighid.
She is the Female Aspect of the Divine... She is the primal force, who came before everything else. She is the originator of the Cosmos. She is the Cycle of Life, and the Turning of the Seasons, the Goddess of birth, beginnings, fertility, generation, reincarnation, prosperity, and abundance. She is birther, sustainer, and giver. She is Healer. She is Wisdom, and Magick. She is the Tao.
She is particularly represented (or manifested) in wind, in rain, rivers and flowing waters, and has been called "Holy Waters from the Sky" - nourisher of the Sacred Oak. She is also associated with the moon - perhaps with Aine, the moon Goddess who protects the crops and livestock, as an aspect of herself. She is mother and queen of the fairies.
When considered to be part of the Morrigan, she is also strife and death, a balance between good and evil, light and dark, the sometimes mysterious and frightening aspect of female energy.
Some believe that Anu and Danu were separate goddesses, and not similar names for the same one. Some that Aine is Anu (I also saw Aine described as the Goddess of love and fertility as well as agriculture)... there are many overlaps and contradictions in what I've read, so it is difficult to pick through them. It is possible that Saint Anne is identified with her, sainted by the Catholics to draw in reluctant Pagans.
As a "triple goddess" she seems to be seen as the maiden aspect, despite her strong "mother" associations, often with Badb as mother and Macha as crone.