The elves of the feywild include: sun and moon, drow, and some other cultures. Each local culture has its own governmental court. There are broad cultural affinities across various courts.
Note, there are material elves who are also called "sun elves" and "moon elves" according to the Forgotten Realms setting. But these equate the high elf and the wood elf, respectively. They are specific cultures in certain regions of the material plane, and go by their alternate names, "gold elves" and "silver elves", respectively, to disambiguate from the fey cultures.
The Norsesque sun elves are manifestations of patterns of sunlight, and normally inhabit high altitudes, high above the clouds of the feywild. In the skyey places where sun courts exist, it is always daytime and the sun is always shining. Time in the feywild is regional rather than temporal. Certain places are always winter, always spring, always summer, or always autumn. Likewise, some places are always day or always night. The famous "twilight forests" of the moon elves are always twilight, an ambiguous blend of after sunset or before dawn, brightly illuminated by moonlight from an unclear source. Mechanically, the moon elves are identical with the eladrin in Mordenkainens Monsters of the Multiverse. The elves of the material plane frequently encounter the moon elves but rarely the sun elves.
The rest of this post focuses on the moon elf culture.
The fey moon elf is Celtesque.
The reallife pillars of the Celtic cultures are: knight, druid, and bard. The three institutions correspond to something like knightly governmental leader, druidic spiritual leader, and bardic scholarly shaman.
These Celtic "knights" are a term of convenience, from a Latin description calling them "equites". They lack the later horse culture, but otherwise seem analogous to the medieval knights, as military families who thereby form a government. Kings and queens can come from these knightly families.
The reallife druids are polytheistic priests of Celtic gods. Originally, their sacred spaces are demarcated clearings in forests, where the priests officiate, but later under Roman influence, they build temples. These priests come from certain sacred families who together comprise a caste system analogous to Hindu Brahmans. They head the community worship and offerings, including occasional human sacrifices for the wellbeing of a valuable leader, whose victims are normally chosen from criminals. The Celtic culture perceives a priest banning an individual from the community offerings as a worst punishment imaginable. But the druids are also the spiritual leaders of a community, such as resolving conflicts between individuals, exhorting holy behaviors, and giving useful advice. A main druidic responsibility is to interpret omens, from natural features such as the behavior of clouds in the sky. Those family members who become an official druid gain a sacred status that forbids the use of weapons, but can fight magically in war instead. After the arrival of Christianity, the outlawing of druids tended to make most druidic family traditions function more like bards. Moreover, the term "druidry" comes to mean a generic term for any and every form of "magic". So there is some confusion within Celtic evidence about later "druids".
Together, the knights and the druids are the main leaders of a Celtic community, something like secular and religious respectively.
The most notable aspect of the bard is as an official in each knightly court. The magic of this bard controls fate and blesses the government with success. These bards speak in poetry without music. Their poetic praise causes blessings, while their poetic satire causes curses. Celtic cultures both revere and fear bards. As court officials, bards and their family members function as scholars. Bards found universities, including famous ones still around today. The academics cover all aspects of known knowledge. Some bardic families are also known for their skills as musicians. Making a living as a pub entertainer can be a shocking juxtaposition of elite and common, causing the bardic family concern but the audience reverence and pride. Bardic family members often function as court advisors, even when not an official bard. Bardic families resemble government technocrats. Celtic myths about bards include the first bard Taliesin as well as aspects of Merlin who is actually a "bard", not a wizard. The mythic evidence makes clear the shamanic function of the Celtic bard. The magic involves fate, mind-magic, and shapeshifting. The magical repertoire of the Celtic manly bard is surprisingly similar to that of the Norse womanly vǫlva. The D&D 5e Bard class derives from the Celtic bard, including its extremely powerful spells, whence slot-9 spells, Shapechange, Foresight, and so on. The 5e Bard is excellent to represent a mythologically accurate Celtic bard.
Worth mentioning, the Celtic bard also associates a protoscience of potion making, involving convoluted ingredients and processes. To some degree, the material components of the D&D Bard class can represent this potion tradition, as well as tool expertise for crafting magic items, herbalism or alchemy generally. Differently, the Norse magic lacks material components, but can imbue ones mind into an object, including the use of runes to write a spontaneous phrase to declare ones intention and focus ones mind within that object. Recent Nordic archeologists have shown that the Viking Period "skald" is in fact the Irish bard. Norse colonies in Ireland and elsewhere in the British Isles hired Celtic bards for their own courts. Norse individuals adopted these Celtic traditions for the Norse language, whence these bardic traditions become prestigious in the Norse courts (Þing) in Scandinavia and elsewhere. Still, where the Celtic bard speaks poetry, the Norse skald sings songs, according to the Norse musical traditions of masculine magic.
In sum, the Celtic bard is a kind of scholarly shaman.
It seems, the reallife Celtic cultures are largely gender fluid or gender neutral. While the prominent leaders tend to be men, there are historically prominent women in all three pillars: knightly queens, later druidic "witches" and possibly earlier druidic priests, and prominent bards. Typically, only a male from a bardic family can officially serve on a court as the bard, but everyone in the bardic family − both girls and boys − grow up learning the bardic magic. Meanwhile the bardic females can advise a court in other capacities. Arguably, some local courts might well have a woman as its official bard.
Relating to the later concept of "fairie" and fairy, the earlier Celtic sidhe are manifestations of the minds of fertile soil. These minds are nocturnally active. The minds often project out from the soil into the form of virtual bodies of "spirits" roaming the fairy realm. Sometimes these spirit bodies materialize into the material world at night. The bodily manifestations of soil love the light of dawn, but the direct light of the sun itself is painfully bright. This aversion to sunlight is a narrative trope, evident in Shakespeare plays and elsewhere. (It isnt the mechanical feature of the drows sensitive darkvision. If for some reason it is important to be in direct sunlight, the fey moon elves can function well enough.) The sidhe, and later their appearance as fey, are fateful yet nocturnal influences.
The gateways between immateriality and materiality are those magical places that are above ground and below ground simultaneously. Such places include:
• A fairy mound whose ground of rock and soil is discretely and conspicuously above flat ground
• A cave, whose cave floor is above ground and below ground
• Airborne dust, whose "pixie dust" is a cloud of dusty soil that is thus both above ground and below ground
• Wearing a patch of cut away grassy soil as if a hat
• A lintel of stone above two posts forming an entrance, such as at Stonehenge
• By extension, being underwater, whose water is above the river bed or lake basin, but below the water surface
All of these places, where the soil is both above and below simultaneously, are a Celtic union of opposites with transcendent magical power. They are reliable places for magic that translates between the solid material plane and the immaterial fey plane.
In the D&D fey setting, the moon elves are Celtesque. Despite the absence of strict gender divisions in reallife Celtic cultures, I want the setting to have them for the moon elves. The gender divisions of the moon elf is less discrete than the gender divisions of Norsesque sun elves. (Compare how today one might expect a CEO to be male, but many female CEOs are known. One might expect a woman to raise young kids, but many men doing so are known.) The other identities are significant minorities within each moon elf gender institution. As all feywild classes are magical, the arcane Wizard functions in place of the "knightly military", rather than a martial Fighter. The moon elf family militias form into armies of Wizards. The nonbinary identity of these Wizards correlates with Corellon, a founder of elven arcane traditions.
While the moon elves are active at night in the material plane, their nonbinary Wizards tend to enjoy time among high elves while their womanly Druids time among wood elves. Their manly Bards tend to remain in the feywild busy at the courts and colleges.
Fey moon elf
• woman: Druid
• nonbinary: Wizard
• man: Bard
