Dheghom Deity - Tumblr Posts
Dhég̑hōm Mā́tēr

Or as I write it, Dhéghom Máter. Her name means "Mother Earth"
She was also called Pḷtáwī or Pl̥th₂éwih₂, meaning "the Broad One", and dʰengwo, meaning "Dark" (dark-skinned?)
Dhéghom is Mother Earth. Associated with plants, nature, fertility, motherhood, cooking and agriculture. She also had a cthonic aspect, being considered both the mother of all life and the place where all living returned to with death. As an ever present mother, oaths were sometimes made by her.
She is sometimes seen as a partner of Dyéus, or of Perkwúnos (or both ;)). Both these sources consider the idea of her being both the mother and consort of Perkwúnos
Offerings
Taken from here
Stones
Symbols of deep waters, earth and grain
Depictions or imagery related to pregnancy
Grains
Green ribbons
Depictions or imagery related to breasts
Depictions or imagery of sows
Devotional acts
Gardening!
Wearing green or brown
Cooking
Educate yourself on local flora and fauna
Eat fruit and vegetables
Learn new recipes involving either vegetables or grains
Make bread
Honor the cycles of nature (seasons, etc)
Picking flowers
Drink natural teas
Ground yourself in nature
Associations
Stones
Vegetation
Fruit
Agriculture
Pregnancy
Motherhood
Landscapes
Sows
Green and brown
the feast of Mabon
Descendants in later pantheons
Cthonia (Greek)
Demeter (Greek)
Semele (Greek)
Plataia (Greek)
Terra/Tellus Mater (Roman)
Ceres (Roman)
Jörd (Nordic)
Prithvi Mata (Vedic)
Finally, here's her wikipedia article