Skinwalker

Somewhere in your bloodline, your ancestors came across an ancient being. Fluid of both morals and form, these changelings, shape-shifters from another world, were neither man nor beast. They were something else... something more. 

Shifter Sense

You may take a bonus action to alter your senses. These include darkvision or Blindsight out to your normal sight range.
You may also eschew one sense to make another stronger. Such as the ability to increase your visual range by three times your normal amount, allowing you to pick out specific details of people, creatures, or objects you are looking at at long range, or tiny objects or creatures you are inspecting at short range. Doing so causes you to become Deafened until you take another bonus action to change it again.
Or you may choose to be able to follow the smell of an object, person, or creature with which you are familiar, up to two miles away. This includes direction, elevation, and approximate range (close, near, far) as long as you have a sample of that person/creature/object's scent. Doing so causes you to become Blinded, as well as Deafened outside of a three foot radius around you.

Skinwalker

At first level, upon choosing the Skinwalker, you may freely transform into a Beast of Challenge Rating 1 or lower.
Once you choose a beast to transform into, you may not transform into another beast for the rest of the day, however, you may freely change into or out of this bestial form as an action. Transforming into a creature grants you a number of temporary hit points equal to that Beast's average or rolled hit points (your choice), for as long as you maintain that form. This transformation lasts until you choose to drop it, or until your Beast Form loses all of its hit points.
Once you change back into your original form again, you return to the number of hit points you had before you transformed. Transforming once more into the Beast gives you the number of hit points your Beast form possessed the last time you transformed, as long as you have not taken a Long Rest -in which case, your beast form's health is returned to its normal level. If you lose all of your Beast Form's hit points, you may not transform again into the Beast until you have completed a Long Rest.

While transformed, you take on the physical Ability Scores (Strength, Agility, Constitution) of that Beast's stat block, as well as its proficiencies (if you already possess those proficiencies, you gain no further bonuses to them) and innate capabilities, such as attacks, and spells contained in its stat block. However, you maintain your own mental Ability Scores (Intelligence, Wisdom, and Charisma) as well as any proficiencies you have, and your alignment. Your items are hidden under your usual form, and you do not have access to them (until later). You can communicate as you would normally (through speech) using any languages you understand to do so, you also gain the ability to speak to any Beast of the same species while transformed. You cannot cast spells while transformed (until that option is enabled upon reaching higher levels within this Subclass)

 

Fluid Form

You may now Choose a new type of creature to be able to transform into.

You may choose between Fey, Fiends, or Aberrations to be able to transform into. 

At 14th Sorcerer level, you may choose again, adding the Dragons, Monstrosities, and Humanoids

At 18th level you may choose 2 more.

 

Aberrations

You may now transform into an Aberration of CR 1 or lower. Doing so follows the same rules as your other transformations.

Dragon

You may now transform into a Dragon of CR 1 or lower. Doing so follows the same rules as your other transformations.

Fey

You may now transform into a Fey creature of CR 1 or lower. Doing so follows the same rules otherwise.

Fiends

You may now transform into a Fiend of CR 1 or lower. Doing so follows the same rules as your other transformations.

Humanoids

You may now transform into any single humanoid creature you have met, or take the form of a Generic humanoid of roughly the same size as you, whose physical characteristics you determine. Doing so grants you the stat block of a Commoner of the chosen race, however, everything else about your appearance changes, including clothes, and other items, and you still have access to your items, and can cast spells without any runic enhancements. Everything else about this behaves exactly the way your other Fluid Form transformations do, but your Humanoid form (read: not your original form) cannot be your altered form. 

Monstrosities

You may now transform into a Monstrosity of CR 1 or lower. Doing so follows the same rules as your other transformations.

Extra Attack

Beginning at 14th level, you can attack twice, instead of once, whenever you take the Attack action on your turn.

Altered Form

You may choose 2 modifications to make to your transformation. These alterations affect a single form. The form these effects apply to is called your altered form. Transforming into another form does not grant the effects of those modifications on that form. The modifications on the altered form persist until you apply them to a new form, which requires the same time, monetary, and material commitment every time you apply it. 

Altered Combat

You may spend the length of a Long Rest to incorporate a rune into your altered form which allows you to add your Charisma modifier to non-spell attacks made while transformed, rather than its Strength or Dexterity modifier. Also, you may add your proficiency bonus to attack rolls made in this way.
Costs 1000g

at the end of which you gain the effect of a short rest.

Armored Hide

You may take the length of a Long Rest to incorporate your untransformed Armor Class into that transformation. Also incorporates any disadvantages.
Doing so applies only to that form. Costs 2000g

Gain the effect of a short rest after doing so.

Formcasting

You may take the length of a Long Rest to incorporate a rune into your transformed body, which allows you to cast spells while transformed.
Doing so only affects one form.
Costs 2000g
At the end of which you do not gain the effect of a long or short rest, but you stave off exhaustion as if you had taken a long rest.

Freeform

You may take the length of a Short Rest to inscribe a rune into your transformation allowing you to change into or out of that form as a free action once per turn. Also you become one size larger (than the form you change into) while transformed.
Doing so costs 750g

At the end of which you do not gain the effects of a short rest, though you do stave off exhaustion as if you had.

Runic Attunement

You may take the length of a long rest to inscribe a series of runes upon your altered form, which translates the effects of an attuned item onto you while transformed. This rune must be applied for each of your attuned items to gain their effect, and consumes the same amount of time and money every time you apply it, and can only be applied once per item. Each rune costs 1/3 the value of the item, rounded up to the nearest gold (based on rarity). This effect is removed if you unattune to that item, or if you do not have it on you when you transform, and returns if you reattune to that item, and have it on you when you transform. 

At the end of which, you gain the effect of a short rest.

Runic Proficiency

You may spend 1/2 the length of a long rest to inscribe a rune onto your altered form. Doing so allows you to add 1/2 of your own maximum hit points (rounded up), as well as your proficiency bonus, to your transformed hit points. Doing so costs 500 gold per application, and the effect can only be applied once for your transformed form. Applying it again removes the effect from the previous application.

At 14th level, you may inscribe this rune again on your altered form, at twice the original cost, allowing you to add your full maximum hit points to your altered form.

At the end of which you gain the effects of a short rest.

Extra Attack or Spell cast

Beginning at 14th level, you can attack three times, instead of twice, whenever you take the Attack action on your turn.
OR
You may cast a second spell, even if you have already cast one, as long as you have the action/bonus action/reaction necessary to do so.