I feel like it would be cool to have different tribes of different elements (e.g. one is water tribe, one is fire, one is lunar, etc.).
They would be located in appropriate areas (example: water tribe would be near ocean, fire tribe could be inside a mountain near lava or volcano biome, lunar is normal village except at night everything glows.).
Each of the traders in the village would have a specialty item related to their village (e.g. water tribe would specialize in fancy fish that you could only get from them, fire would have spicy foods, lunar would have stuff that glows in the dark)
Each of the villages have a special trait to offer (e.g. Water tribe lets you fish faster, fire tribe lets you smelt/cook quicker, etc.)
Lastly, with each type of village comes a fancy end-game boss. In order to find this boss, you must obtain a map to the bosses location. This can only be obtained by trading items with certain villagers. Once you have collected all (e.g. 4) parts of the map, you can now find the portal to the that tribe's end game boss.
Portal is Underwater (needs potion of water breathing)
Boss is Giant Eel that shocks within a water-filled temple.
Mechanic: Don't stand in the water during shock. Dodge Static Electric Balls.
Portal is within Lava
Boss is Fire Giant that spreads fire within a temple of falling lava.
Mechanic: you must put out the fires otherwise it will consume you. Dodge fireballs.
Portal can only be accessed at night
Boss is in pure darkness and you must use light/moon in order to see it and thusly attack it
Mechanic: you must light up the room in order to know what to attack. No light = no damage. Boss regularly attacks light source, so keep the lights up
Portal is within ground
Boss is changes inhabits the ground and can move with anything touched to the ground.
Mechanic: you most dodge rocks throw at you while you slowly mine away at the ground to trap the boss in a certain patch of dirt. Once it reaches low life, it transforms into rock golem and normally fight it.