Druid

Source: Grim Hollow Pg 48

The Circle of Blood is a keeper of old ways. They remember how ancient druids performed sacrificial Circle spells rituals under a blood-red moon to appease the uncaring forces of nature. The Circle of Blood druid trades blood for life in a delicate balance to bolster their allies and destroy their enemies.

Source: Dragon Stew, Pg 35/ Hexbound, Pg 17

When mentioning the word witch, many instantly think of the witch druids belonging to the Circle of the Brew. Circle of the Brew witches worship nature and spirits equally, and use both in their witchcraft. They see the natural world as a giver of blessings, and it’s their duty to take those resources and transform them to suit their needs, and they do so with the help of spirits.
They distill the natural and spiritual energies into powerful magical brews that they can then ingest or have others ingest to wondrous results. Because of their unconventional practices and their insistence on changing and shaping the natural world to suit their needs, Circle of the Brew druids are the odd ones out of all the druid circles. They are the most likely out of all druids to live close to or even in civilization, sharing their magic with those who need it. Many Circle of the Brew druids become famed healers and apothecaries. They fit perfectly, however, in the world of witch covens. Many Circle of the Brew druids are the designated healers and pharmacists in enormous covens, and they also tend to be among the richest witches because of their incredible magical potions.

Source: Guide to Drakenhime, Pg 156

As druids are often in tune with nature and the natural order, most see delerium as a scourge upon the world. However, a rare few see the truth: the eldritch stones are an essential part of the natural order, one which works at a cosmic scale. Druids of the Circle of Contamination use the blighted rocks and contaminating Haze as a conduit for supernatural evolution. They have embraced the chaotic power of Delerium as an extension of the inherent chaos in the natural order, spreading the Haze while wielding it as a powerful ally to fuel their spells.

Source: Xanathar's Guide to Everything

Druids who are members of the Circle of Dreams hail from regions that have strong ties to the Feywild and its dreamlike realms. The druids’ guardianship of the natural world makes for a natural alliance between them and good-aligned fey.
These druids seek to fill the world with dreamy wonder. Their magic mends wounds and brings joy to downcast hearts, and the realms they protect are gleaming, fruitful places, where dream and reality blur together and where the weary can find rest.

What to Expect A niffty subclass revolving around some cool tricks mainly around support, rest and movement. able to heal allies with a unique resource, Create a safe/buffing zone during rest moments and the ability to teleport short distances without the use of a spell. and to top it off at later levels you wake up each day starting with breakfast and a free cast of some high level spells

Source: Floral Dragons

The first druids of the Circle of Flowers were people who sought out and bonded with floral dragons. The druids learned how to imitate floral dragons’ forms and unique existence as beings that blend plants and animals. Now, these druids protect the floral dragons who first inspired their circle as well as the balance of nature in both its beauty and ferocity.

Source: MCDM Arcadia Vol 5

When legends tell of archdruids protecting the land, they speak of antlers, gnarled oak staffs, and swarms of birds. This is, of course, by design. Circle of the Gilded druids protect places much more valuable, fraught, dangerous… and best kept secret.
Filled with precious gems and ores, these sites would be strip-mined by covetous tyrants to fuel their generations-long war efforts. By inlaying the metals and gems into their very bodies, druids of the Circle of the Gilded tap into the ancient, primordial powers contained within these minerals to defend this lifeblood of the earth. Their zeal is often mistaken for greed, but the druids valiantly guard a resource often considered more valuable than humanoid life.

Source:
Player's Handbook, Pg 68
(Core)

The Circle of the Land is made up of mystics and sages who safeguard ancient knowledge and rites through a vast oral tradition. These druids meet within sacred circles of trees or standing stones to whisper primal secrets in Druidic.
The circle's wisest members preside as the chief priests of communities that hold to the Old Faith and serve as advisors to the rulers of those folk. As a member of this circle, your magic is influenced by the land where you were initiated into the circle's mysterious rites.

What to Expect the land gives you some extra spell access based on a particular habitat some spell slot recovery on a short rest, ease of movment through difficult terrain, some poison immunity and resistances to effects by elementals/fey at later levels and to top it off you can scare off certain nature based creatures from being able to attack you.

2024 Revision Available

Source:
Player's Handbook, Pg 69
(Core)

Druids of the Circle of the Moon are fierce guardians of the wilds. Their order gathers under the full moon to share news and trade warnings. They haunt the deepest parts of the wilderness, where they might go for weeks on end before crossing paths with another humanoid creature, let alone another druid.
Changeable as the moon, a druid of this circle might prowl as a great cat one night, soar over the treetops as an eagle the next day, and crash through the undergrowth in bear form to drive off a trespassing monster. The wild is in the druid's blood.

2024 Revision Available

Source: Grim Hollow Pg 49

Druids of the Circle of Mutation believe that nature should be improved in order to compete with the unnatural world. Their order hides in the darkest corners of swamps and forests, conducting experiments to warp the structure of their domain. They go unheard from for months on end, emerging from the wild with twisted vines and mutated creatures at their side. These druids have earned the scorn of other circles, discredited as those who have lost their way. In the eyes of a mutation druid, those who wish to preserve nature as it is simply fear what change brings.

Source: 2024 Player's Handbook

Become One with Tides and Storms
Druids of the Circle of the Sea draw on the tempestuous forces of oceans and storms. Some view themselves as embodiments of nature’s wrath, seeking vengeance against those who despoil nature. Others seek mystical unity with nature by attuning themselves to the ebb and flow of the tides, following the rush of currents and waves and listening to the inscrutable whispers and roars of the winds.

Source: Xanathar's Guide to Everything

Druids of the Circle of the Shepherd commune with the spirits of nature, especially the spirits of beasts and the fey, and call to those spirits for aid. These druids recognize that all living things play a role in the natural world, yet they focus on protecting animals and fey creatures that have difficulty defending themselves. Shepherds, as they are known, see such creatures as their charges. They ward off monsters that threaten them, rebuke hunters who kill more prey than necessary, and prevent civilization from encroaching on rare animal habitats and on sites sacred to the fey.
Many of these druids are happiest far from cities and towns, content to spend their days in the company of animals and the fey creatures of the wilds. Members of this circle become adventurers to oppose forces that threaten their charges or to seek knowledge and power that will help them safeguard their charges better. Wherever these druids go, the spirits of the wilderness are with them.

Source: Tasha's Cauldron of Everything

Druids of the Circle of Spores find beauty in decay. They see within mold and other fungi the ability to transform lifeless material into abundant, albeit somewhat strange, life. These druids believe that life and death are parts of a grand cycle, with one leading to the other and then back again. Death isn't the end of life, but instead a change of state that sees life shift into a new form.
Druids of this circle have a complex relationship with the undead. They see nothing inherently wrong with undeath, which they consider to be a companion to life and death. But these druids believe that the natural cycle is healthiest when each segment of it is vibrant and changing. Undead that seek to replace all life with undeath, or that try to avoid passing to a final rest, violate the cycle and must be thwarted.

Source: Tasha's Cauldron of Everything

The Circle of Stars allows druids to draw on the power of starlight. These druids have tracked heavenly patterns since time immemorial, discovering secrets hidden amid the constellations. By revealing and understanding these secrets, the Circle of the Stars seeks to harness the powers of the cosmos.
Many druids of this circle keep records of the constellations and the stars' effects on the world. Some groups document these observations at megalithic sites, which serve as enigmatic libraries of lore. These repositories might take the form of stone circles, pyramids, petroglyphs, and underground temples; any construction durable enough to protect the circle's sacred knowledge even against a great cataclysm.

2024 Revision Available

Source: Tasha's Cauldron of Everything

Druids within the Circle of Wildfire understand that destruction is sometimes the precursor of creation, such as when a forest fire promotes later growth. These druids bond with a primal spirit that harbors both destructive and creative power, allowing the druids to create controlled flames that burn away one thing but give life to another.