ProWorld is a Unity editor extention to easily and quickly procedurally generate terrain, textures, foliage and more.
The extension uses a node based system to easily generate maps.
A video demonstration can be found here
ProWorld is highly optimized and utilizes multiple threads which allows work to be done in background without the Unity editor freezing up. It also includes an auto save feature when compiling or playing to prevent loss of work.
2.0 Brings a whole slew of new features including real-time terrain, preview window, live updates on terrain and more...