The first people were not farmers, they didn't concern themselves with the earth they worried about the hunting and fishing, the forests, mountains, and the water. Thus the most important goddesses in ancient lore was not the earth mother, rather they were the spirit owners of specific places.
In Selkup lore a forest goddess could appear to hunters and give them great skill, while in Japan the Kami of the mountains were most often goddesses who had a close relationship with hunters. Other Siberians would talk of a women who gave birth to magical reindeer, sometimes with eight legs, that would help shamans. Just as Loki in his female form gave birth to an eight legged horse that helped Odin. This has lead to the notion of the "Deer Mother."
More common in folktales from Japan and Europe, however, is the importance of female water spirits, which could often take the form of serpents. In the earliest lore we have from Japan it was female water kami that could take serpent form which ruled the mountains. In Northern Italy it's female water spirits that take the form of Golden snakes the cause the plants in a region to grow. Just like the nymphs of Ancient Greece, the Nixies of Germany. These water spirits were commonly believed to possess early shamans giving them the skills and knowledge they needed to build and protect civilization.
So as civilization adapted the water goddesses transformed from being spirits of fishing and clean water to being spirits of farming and civilization. Indeed the idea of muses, and fate spinners is likely based on these early hunting and fishing goddesses. Indeed the Celts believed that skills from poetry, ship building came from the will female fairy like beings. Further in parts of Eastern Europe people held rituals to honor the water goddesses contributions to agriculture, weaving, and civilization into the modern era. Yet oddly enough the focus shifted away from this multitude of goddesses, of fairies, towards beings like Gaea, for which we have no evidence of extensive worship in most places. Indeed the Siberian people's didn't start worshiping any form of Earth Mother until the introduction of agriculture, while the Greeks, Celts, etc didn't pay much attention to her, and the Japanese primarily worshiped local mountain goddesses until they were conquered by the Imperial Court and forced, often with violence to recognize the Imperial ancestor, the Sun Kami as the primary deity.
Interesting points for Writers
Raised By Heroes
Nymphs in mythology founded cities, raised Zeus, and heroes, just as they raised Heroes in Germanic, Russian, and Celtic lore.
Protectors of the Land
Each land is protected by a deity, most often female. This deity helps the animals and plants thrive, inspires the people of the land, and protects them from evil spirits. If she gets sick, comes under attack, or is killed the region would unravel. In Japanese and Greek mythology she would often call on hunters to help her fight off evil, unclean enemies.
In Celtic lands the fairies often needed human knights to help them, for humans had iron and other magical devices weapons which they could not touch.
Further if one of these goddesses died a new one would have to be sought out, otherwise the land and it's people would die with her.
Descended from the Goddess
The people of a region were very often descended from a goddess's union with a hero figure. The people of Arcadia Greece, for example, were the children of a nymph who determined what the moral standards of the city would be and enforced these moral standards. She did this not only as the goddess of the city, but as the grandmother of the people who lived within it.
There are tales throughout the world of a man who marries a fairy figure of some form, has children, only to have the fairy eventually leave him. Yet she still watches over her children in secret. There are a number of reasons why she can't show herself to her children directly. Such as the fact that humans have the power of the evil eye which can harm fairies, or humans are impure which can also do them harm. In Russia it was believed that sins hurt fairy like creatures, and that humans eventually became so sinful the fairies had to flee the land. In Japan impurity (such as dirt, blood, death, etc) caused kami to loose their power. While in Western Europe if a human gazed at a fairy it could actually hurt the fairy, preventing it from using their magic.
So while humans may be descended from a fairy like beings which love them as a grandmother would, this fairy like being can only show itself to a few people.
Lament of Ur and Jenny Greenteeth
There is an ancient Mesopotamian poem called "The Lament of Ur" in which the founding goddess of Ur morns the destruction of her city. A ghost city to which she is now tied.
Jenny Greenteeth is a water spirit of Shropshire next to Wales, and is likely a former water goddess similar to those found in Wales. Except her land was conquered and her people destroyed. So she was forgotten and left alone.
These are essentially ghost goddesses.
Jacob Grimm tells of many of these ghost goddesses throughout Germany who've lost the ability to speak, but will still occasionally show people hidden treasures.
These spirits are lonely refugees from a forgotten world, though they appear to occasionally try to get their old world back. Nymphs and Jenny Greenteeth, among others will often possess people just as they used to, likely hoping to gain another shaman, but in the modern day this is often considered to be an attack, as possessions cause people to have violent reactions at first, thus the spirit is exorcised.