Circle of the city

The Circle of the City is made up of druids living in cities to
 guard and to maintain the balance between nature and
 civilization. Druids of this circle do not reject technology and
 metal, but rather are very pragmatic about the tech they use.
 This circle thinks that metals come from the earth, and
 because of that, they have a natural place in the world.

Bonus Proficiencies

Starting at 2nd level, you gain proficiency with dart guns and
 pistols (including machine pistols).

Metal Wild Shape

Also at 2nd level, whenever you use your Wild Shape feature,
 your shape is made with metal and pieces of the city, more
 simmilar to a construct than a beast. While transformed into
 a beast, your AC increases by your proficiency bonus and the
 Constitution score of the shape increases by 2.
 Starting at 6th level, the Constitution score of the shape
 increases by 4.

Construct Mind

At 6th level, while transformed into a beast, you are
 considered a construct, you gain a +1 bonus to attack rolls
 and your attacks count as magical for purpose of overcoming
 resistance and immunity to nonmagical attacks and damage.
 At 8th level, the attack bonus increases to +2

City Guardian

At 10th level, you can wild shape into a city guardian for 1
 minute. After using this feature, you must finish a long rest to
 use it again.

True Construct

At 14th level, you cannot be charmed, paralyzed, petrified or
 poisoned and you are immune to poison and psychic damage.
Additionally, you can wild shape into a city guardian twice
 before a long rest