Games Workshop make fantastic models, and their Imperial terrain is absolutely superb. Unfortunately, if you don’t want imperial type terrain (or a hill or two), you are pretty much out of luck!
Lets take a look at what we can find for terrain for other races, or cheaper alternatives for a home board!
There are some very good Eldar pieces of terrain available on the market at the moment.
Minature Scenery in Australia do some fantastic MDF pieces, which can easily fill in the traditional roles of bastion (Elven Tower) :
A Skyshield Landing Platform (or Elven Dias):
And, of course, an Aegis Defense Line (or Sanctuary of Souls):
In addition, their walkways and space modulators are fantastic for people putting together an Eldar themed board.
Brush 4 Hire do an interesting range of Aegis Defense Line alternatives, one of which works quite well as an advanced Eldar concept – their forcefield defines line! You can pick the colour of the translucent plastic force shield, to match your craftworld a bit better!
Micro Art Studios do a fantastic set of barricades or Aegis defines line too!
There once was a template for creating your own webway gate on the GW site, but like much of the old school hobby stuff, this has long since been removed. A retro-engineered version can be found on a here, though!
I’m sure there are a few more options out there – I’ll update this post if/when I come across them!