I haven't got many ideas to contribute, but this is an awesome thread! I'm loving all the ideas!
Maybe a paranormal town? In my town I will have Bigfoot, aliens, a lake monster, and a haunted house. Maybe the mayor could be a paranormal investigator? I don't know.
I really like the idea of a post-apocalyptic wasteland that someone mentioned earlier.
What about a farm town? There are so many farm animals to choose from, chickens, cows, pigs, sheep, goats, etc. Include some fruit orchards, some fence patterns, and some appropriate public works projects (the scarecrow comes to mind). That could be neat.
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Also, another color you could add to your color themes is black. There are enough black and darker color villagers and with some dark paths and black flowers and mostly cedar trees, I think that'd be a neat looking town.