Procedural Worlds
Procedural Worlds was co-founded by two technology veterans and serial entrepreneurs, Adam Goodrich, and Rand Leeb-du Toit.

They bring the real world into the virtual to simulate it, automate it and, ultimately, empower people to make sense of the real world and better manage their lives.

Their powerful tool will let you shape the world using GAIA, populate it with foliage and props, where GENA 2 is a masterpiece in that field, create paths using Path Painter, and form collaboration with Nature Manufacture CTS - Complete Terrain Shader was born, which lets you achieve beautiful terrains.

This is one of the top Asset Store publishers, but check the ratings and see for yourself.

CTS - Complete Terrain Shader

Path Painter