Auto-Terrainer is an intuitive tool designed to transform low-poly meshes into detailed, customizable 3D landscapes capable of creating "mountains, valleys, islands, deserts, forests, and much more." The tool utilizes a combination of subdivision and displacement to turn low-poly geometry into a realistically textured ground surface, allowing users to control the overall shape and details through simple slider controls.
The add-on comes with an intelligent material that textures the terrain according to the surface gradient, generating vegetation on flatter areas. The author notes that Auto-Terrainer is "not a one-size-fits-all magic preset for all your terrain needs," but seemingly a quick way to obtain an impressive base terrain that can then be further customized manually, as demonstrated in this video for the original release.
There are also two commercial versions: the Pro version with higher resolution textures and more foliage options, and the Desert version for creating desert environments. Both editions cost $5 each.