Little magical hearth-beings, whatever.
What do they do? They automate some things.
Steel crucible running? Give a brownie some coal, and they'll fuel it up when needed.
Silkmoths going? Brownies will collect them and feed them.
Tired of ferrying goods? Brownies will carry things around your village for you.
Basically, an in-world source of automation; You could fuel them with experience, or maybe you have to summon them with hearth magic and they only remain for a period of time, after which you need to resummon them. Maybe the maximum you can summon is based off a stat, who knows.
Basic automation could be as simple as designating a 'source' inventory and a 'target' inventory, as well as maybe a 'quantity' - the brownie will always try to pull from the source inventory (stockpile, cupboard, etc) and place into the exit.
Could it be more complex? Yeah sure. Take inspiration from minecraft mods.