A suffusion of yellow
I mostly like this list, but I would prefer to include a summoning/animal companion focused option. Circle of the Primeval from the Giants UA had a good framework for this, albeit with flavor that was more specific than it needed to be. Putting aside the Circle of Stars (which is a good option in Tasha's but recent enough and narrow enough to wait for a revision), this would give a PHB lineup with a Beast Shape Druid, Elemental Druid, Healing Druid and Animal Compainion Druid, which I think would cover a wide range of character concepts and would have at least one subclass enhancing each Channel Nature option.
seems like the Animal companion schtick has been given to Beast master and Drakewarden Rangers rather than Druids who are about Wildshaping rather than Companions.
I dont mind that too much really
Land/Earth- Caster Druid. Upgrades Healing Blossoms for more healling
Moon- Shapeshifter Druid. Upgrades Wildshape to stronger beasts
Stars-Hybrid Druid. Gains Starry Form
Sun- Elemental Druid. Gains Elemental Shape and Cauterize
Earth - Elemental - Earthquake, Volcano, Flood, Storm, Spores
Moon - Wildshape Beasts and monsters
Stars - Casting (Circle of Dreams?)
Sun - Healing Light