(A variation on the Fighter subclass Arcane Archer, found in Xanathar's Guide to Everything, re-imagined for the Ranger class.)

Utilizing ancient Elven techniques to imbue arrows with nature magic, Druidic Archers are formidable marksmen whose origin hearkens back to the elite warriors responsible for protecting the boundaries of Elven civilization. These warriors wield magic to improve their aim and track targets, helping them defend the primeval woodlands and hidden glades with an unparalleled accuracy. As part of the training required to turn a skilled archer into one of these legendary warriors, recruits must display an aptitude for arcane magic, but also a deep respect for the natural world, much in the same way that the elves who teach this discipline do. As such, many individuals who fall into the loose category of 'rangers' feel an affinity with this Elven tradition, and so learn it's secrets to aid their fights in the wild places of the world.  

Druidic Archer Training

At 3rd level, you learn some of the secrets of nature magic that are typical for practitioners of this elven martial tradition. You choose to gain proficiency in either the Arcana or the Nature skill, and you learn the Druidcraft cantrip.

In addition, you learn how to whisper to nature spirits to reveal to you the location of targets that hide from your aim. As a bonus action on your turn, you can choose one creature that you can see within 60ft of you to become the focus of your aim. Whilst a creature is targeted in this way it cannot benefit from half or three-quarters cover, and you mentally know its location whilst it remains within 60ft you, even if it is Invisible. This benefit lasts until the start of your next turn.

Arcana

You become proficient in Arcana.

Nature

You become proficient in Nature.

Druidic Archery

At 3rd level, you learn to unleash special magical effects with some of your shots. When you gain this feature, you learn two Druidic Shot options of your choice (see “Druidic Shot Options” below).

Once per turn when you fire an arrow from a shortbow or longbow as part of the Attack action, you can apply one of your Druidic Shot options to that arrow. You decide to use the option when the arrow hits a creature, unless the option doesn’t involve an attack roll. You have two uses of this ability, and you regain all expended uses of it when you finish a short or long rest. Additionally, you can use an action to expend a 2nd level spell slot or higher to regain one use of this ability.

You gain an additional Druidic Shot option of your choice when you reach certain levels in this class: 5th, 10th, 15th, and 20th level. Each option also improves when you become an 11th-level Ranger, and again when you become a 20th-level Ranger.

Druidic Shot Options

The Druidic Archery feature lets you choose Druidic Shot options for it at certain levels. The options are presented here in alphabetical order.

If an option requires a saving throw, your Druidic Archery save DC equals 8 + your proficiency bonus + your Wisdom modifier.

Banishing Arrow

Empowering your arrow with abjuration magic, you attempt to banish the target to gloomy hollow in the Feywild. The creature hit by the arrow must succeed on a Charisma saving throw or be banished. While banished this way, the target is incapacitated and its speed becomes 0. At the end of its next turn, the target reappears in the space it vacated or the nearest unoccupied space if that space is now occupied.

When you reach 11th level in this class, the arrow deals an extra 2d6 psychic damage on a hit. When you reach 20th level in this class, this damage increases to 4d6 psychic damage.

Beguiling Arrow

Your enchantment magic causes this arrow to temporarily beguile its target. The creature hit by the arrow takes an extra 2d6 psychic damage, and choose one of your allies within 30 feet of the target. The target must succeed on a Wisdom saving throw, or it is charmed by the chosen ally until the start of your next turn. This effect ends early if the chosen ally attacks the charmed target, deals damage to it, or forces it to make a saving throw.

The psychic damage increases to 2d6 when you reach 11th level in this class, increasing again to 4d6 when you reach 20th level in this class.

Bursting Arrow

You imbue your arrow with force energy drawn from the school of evocation. Immediately after the arrow hits the creature, the target and all other creatures within 10 feet of it take 2d6 force damage each.

The force damage increases to 4d6 when you reach 11th level in this class, increasing again to 6d6 force damage when you reach 20th level in this class.

Enfeebling Arrow

You weave necromantic magic into your arrow. The creature hit by the arrow takes an extra 2d6 necrotic damage. The target must also succeed on a Constitution saving throw, or the damage dealt by its weapon attacks is halved until the start of your next turn.

The necrotic damage increases to 3d6 when you reach 11th level in this class, increasing again to 4d6 necrotic damage when you reach 20th level in this class.

Grasping Arrow

When this arrow strikes its target, conjuration magic creates grasping, poisonous brambles, which wrap around the target. The creature hit by the arrow takes an extra 2d6 poison damage, its speed is reduced by 10 feet, and it takes 2d6 slashing damage the first time on each turn it moves 5 foot or more without teleporting. The target or any creature that can reach it can use its action to remove the brambles with a successful Strength (Athletics) check against your Druidic Archery save DC. Otherwise, the brambles last for 1 minute or until you use this option again.

The poison damage and slashing damage both increase to 4d6 when you reach 20th level in this class.

Paralyzing Arrow

You use enchantment magic to wreathe your arrow in paralytic lightning. The creature hit by this arrow must make a Constitution saving throw or be paralyzed as the crackling lightning encapsulates its body. The target can repeat this saving throw at the beginning of each of its turns or when it takes damage from a creature, freeing itself from the paralysis on a successful save.

The arrow deals an additional 2d6 lightning damage when you reach 11th level in this class, again increasing to 4d6 lightning damage when you reach 20th level in this class.

Petrifying Arrow

You empower your arrow with potent transmutation magic. When a creature is struck by this arrow, its speed is also halved until the start of your next turn, and it must succeed on a Constitution saving throw or become restrained as its flesh begins to turn to stone. A creature restrained by this effect must make another Constitution saving throw at the start of its next turn. If it succeeds, it is no longer restrained and the effects of the arrow end. If it fails, it is turned to stone and becomes petrified until the start of its next turn.

When you reach 20th level in this class, the target's speed is reduced to 0 when the arrow hits, until the start of its next turn.

Piercing Arrow

You use transmutation magic to give your arrow an ethereal quality. When you use this option, you don’t make an attack roll for the attack. Instead, the arrow shoots forward in a straight line, which is 1 foot wide and 60 feet long, before disappearing. The arrow passes harmlessly through objects, ignoring cover. Each creature in that line must make a Dexterity saving throw. On a failed save, a creature takes damage as if it were hit by the arrow, plus an extra 1d6 piercing damage. On a successful save, a target takes half as much damage.

The piercing damage increases to 2d6 when you reach 11th level in this class, increasing again to 4d6 when you reach 20th level in this class.

Seeking Arrow

Using divination magic, you grant your arrow the ability to seek out a target. When you use this option, you don’t make an attack roll for the attack. Instead, choose one creature you have seen in the past minute. The arrow flies toward that creature, moving around corners if necessary and ignoring three-quarters cover and half cover. If the target is within the weapon’s range and there is a path large enough for the arrow to travel to the target, the target is automatically hit by the arrow. Otherwise, the arrow disappears after traveling as far as it can. The target takes damage as if it were hit by the arrow normally.

The arrow deals an additional 2d6 force damage when you reach 11th level in this class, increasing again to 4d6 force damage when you reach 20th level in this class.

Shadow Arrow

You weave illusion magic into your arrow, causing it to occlude your foe’s vision with shadows. The creature hit by the arrow takes an extra 2d6 psychic damage, and it must succeed on a Wisdom saving throw or be unable to see anything farther than 5 feet away until the start of your next turn.

The psychic damage increases to 3d6 when you reach 11th level in this class, again increasing to 4d6 when you reach 20th level in this class.

Empowered Archery

At 7th level, you can further empower your archery with ancient magic.

Whilst you are wielding a longbow or shortbow, non-magical projectiles fired from this weapon count as magical for the purpose of ignoring resistance and immunity. Non-magical projectiles that have been made magical by firing them from this weapon lose their magic at the start of your next turn and are magically returned to your quiver as non-magical arrows, ready to be used again.

(Magical arrows other than the ones created by this feature, such as Arrows of Slaying, still lose their magic as normal when they satisfy their usual criteria).

Curving Shot

Also at 7th level, you learn how to re-direct errant arrows towards other targets of your magic. When you make a ranged attack with an arrow fired from your bow and miss, you can use your reaction to magically re-direct the errant arrow towards another creature that you can see within 60ft of the original target, making another attack roll against the new creature. You can use this feature once per turn.

Elven Expertise

At 11th level, your study of Elven archery techniques has granted you the discipline to keep your aim steady in dangerous situations. Being within 5ft of an enemy when you make a ranged attack roll no longer imposes disadvantage on the roll.

In addition, you have delved further into your study of Elven and Druidic lore. You learn how to read and write Druidic and learn one 1st or 2nd spell of your choice from the Druid spell list. This spell counts as a Ranger spell for you and does not count against your spells known.

Well of the Ancients

At 15th level, you can draw deep upon the residual nature magic that lingers around you ensure your Druidic Archery is available whenever battle starts. If you roll initiative and have no uses of Druidic Shot remaining, you regain one use of it.