I have an idea for Prison in minetest. It is widely seen on minecraft, and this will attract newcomers.
Prisons is where you mine and sell, and occasionally pvp with others, and basically
But I have a twist.
You can explore outside the prison, aka 'break out', but you will need to come back and buy tools:
Tool crafting will be disabled, so they need to stay near the prison or remember where it is, and come back every now and then to sell and buy things.
There will be protection, but you will have to buy them, and they are one-use.
That way, there are more options for it.
Hope ya have a great day!