I would definitely say add a new kingdom/faction if you’re looking for a time consuming labor intensive pursuit. Perhaps playable goblin faction or undead. Not only would that give you a ton of stuff to work on, it would spark other modders to make appropriate furniture and decorative items.
In fact I believe @Fornjotr had already started working on some goblin decorations…at least I think they were his…
I’d recommend checking to see if someone is working on an actual goblin kingdom with him to avoid steppin’ on any toes. Oh yeah and I believe @BrunoSupremo supplied the swamp, but I could be wrong.
Edit: Okay given the info @BrunoSupremo just shared I’d say Undead faction + biome would probably be wildly popular. Especially reworking all the classes to fit into the theme.