Mechanical Gnome (5e Subrace)
From D&D Wiki
Mechanical Gnomes are small automata, often made from tin. They look like tiny, fat, adorable soldiers with funnel hats. They were created by the Dwarves long ago for an unknown purpose. Perhaps the Dwarves were happy that they were taller than another race and wanted to rub it in the Gnomes' faces. It is rumored that Mechanical Gnomes' gears keep ticking even in the belly of a Hydra. Maybe that was their purpose.
Ability Score Increase. Your Constitution score increases by 1.
Metal Body. While you are not wearing any armor, your armor class equals 10 + your Dexterity modifier + your Constitution modifier. Your base walking speed is 20 feet.
Tunneler. You know the mold earth cantrip. Constitution is your spellcasting ability for it.
Mechanical Whirring. While you are awake, you make a quiet humming sound audible to anyone within 15 feet of you. You have disadvantage on stealth checks against anyone within 15 feet of you.
Automaton. You do not need to eat, drink or sleep, but you do need to have someone else wind you for at least 5 minutes each day (every 24 hours) or you will become unconscious until the next time someone winds you. You can sleep by inserting a pin, needle, or similar object into your gears. Time spent asleep does not count down your remaining hours to unconsciousness, but you can not wake up until someone else removes the pin from your gears.