I would highly recommend either Deaths or Bloods runes.
This is probably your best choice for creating any goldfarm, as Nature Runes requires no-any questing, and are therefor the most choosen one.
Wich is why it doesnt gives any gp/hr anylonger.
I personally used to have 10x Nature Rune goldfarmers, i have fully quit Runecrafting for goldfarming now, but thats because i dont bother paying someone to do all the questing on that much accounts.
But overall, i'd say either do Deaths or Bloods.