The best part about JDMG is that it is set in a world that is everything you can think of. You can be fighting in a hypertech building one fight, then when you get to ground floor it is equivalent of modern day streets, then catch a bit of Barrier Duty and you have the wasteland terrian, go down the road to apetown and you have forests and jungles. Want craters, do a tour on the moon or mars.
There really is no specific terrain to Judge Dredd. Go with what you want.
Although a few good options are
World works games is VERY high quality but also lots of work.
Microtactix is simple, nice and quick. It's mainly what I use.
Then if you really have the money, http://www.antenocitisworkshop.com/wargames-scenery-terrain/sci-fi-scenery-terrain.html?p=2