Hex Lands [1.12.2]
This mod changed standard world generation into a hex based tiles, similar to a board game. Each hex will contain one biome, and hexes with the same biome will connect together. Config options allow for adjustments of hex size, terrain height, changing block that outlines hexes, and more. Hex worlds are created by selecting "World Type: Hex Lands" when creating a new world. Other than changing height and shape of biome, other feature should generate normally (villages, caves, ravines, lakes, etc). This mod should also work with extra mod biomes like Traverse and Defiled Lands.