Demi golems, basically smaller less powerful golems with living fleshy insides.

Spoiler
Show
Demi golem
Demi Golems are made through the process of building a case of a golem material around a fresh corpse with the heart of the corpse replaced with a rare gem that traps the creature's soul.
When the runic symbol for life is inscribed on the golems chest is rises as a demi golem. The demi golem retains its memories and intelligence from itís past life.

Demi golem traits
Ability score increase. Your constitution increases by 2.
Age. Demi golems do not age.
Alignment. The demi golem retains its alignment from itís past life.
Size. Demi golem are often larger then the average human, however their size is still medium.
Speed. Your base walking speed is 30 feet.
Living construct. Your creature type is both construct and humanoid as such you can be targeted with spells and effects that only target those types of creatures. When you are targeted with a healing spell that has no effect on constructs, subtract 1d4 from the hit points you heal. Though if you are targeted with the mending spell the caster can spend a first level slot to heal 1d8 + their spellcasting modifier hit points from you.
Cling to life. Being mostly made of inorganic material makes it really hard to kill you. Whenever you roll a 16 or higher on a death saving throw you regain 1 hit point.
Constructed resilience. You are mostly made of some kind of substance but still have flesh beneath. You have resistance to poison damage and have advantage on saving throws against the poisoned condition.
Languages. You can speak common and another language of your choice.
Subraces. Choose one of the following subraces.

Clay Demi Golem
Ability score increase. Your dexterity increases by 1.
Hardened clay. Your armor class cannot be lower than 13.
Acid resilience. You have resistance to acid damage. When you take acid damage you gain temporary hit points equal to your constitution modifier immediately after you take the damage.
Haste. Once per short or long rest you may make a single melee attack as a bonus action, while you do this you gain a +2 bonus to your armor class until the beginning of your next turn.

Flesh Demi Golem
Ability score increase. Your strength increases by 1.
Fleshy coat. When you take damage you may use a reaction to reduce it by half your constitution modifier rounded up (minimum of 1).
Lightning resilience. You have resistance to lightning damage. When you take lightning damage you gain temporary hit points equal to your constitution modifier immediately after you take the damage.
Unnatural hardiness. Your hit point maximum increases by 1 and increases by an additional 1 each time you gain a level.

Iron Demi Golem
Ability score increase. Your strength increases by 1.
Iron skin. Your armor class cannot be lower than 16.
Fire resilience. You have resistance to fire damage. When you take fire damage you gain temporary hit points equal to your constitution modifier immediately after you take the damage.
Poison breath. You know the poison spray cantrip. Constitution is your spellcasting ability for this spell.

Stone Demi Golem
Ability score increase. Your wisdom increases by 1.
Stone skin. Your armor class cannot be lower than 15.
Statuesque figure. When you stand motionless you are indistinguishable from a common statue.
Slow time. As an action you can warp time around you, causing each creature in a 10 foot radius sphere centered on you (including you) to be stunned every other turn for the next minute. This effect end when you lose concentration (as if you were concentrating on a spell).