Terrain Generation Tools

I have just purchased the s&box and am downloading it now.  I was wondering if there are any terrain generation tools available for hammer/map editor?

My searches are only bringing up results that work with older versions of Hammer like Nem's tools, and apparently that dosen't work with Source 2.

You have a few, just look for something that export a heightmap

Thanks for the reply.  Heightmaps aren't a problem to create, but is that all that can be imported?  I was thinking more along the lines of tools that also generate other aspects of the terrain, like texture masks/materials etc.  

Now I have s&box installed I have learned that materials and even splatmaps can be imported from terrain generation tools if they are in the correct format.