After deciding to stick with 15mm scale terrain, I spent some time in the last few days organizing what I had and building some additional pieces.
Here is the terrain I currently have. Most of it fits in a storage box (38cm x 24cm x 18cm) and some older, simpler buildings and tiles are stored in a plastic folder.
So, what exactly is in the box? Plenty of stuff, useful for modern, post-apocalyptic and sci-fi gaming.
First, there are 10 flat-folding buildings based on WorldWorks Games swift scenics line, more specifically the office and abandoned buildings.
There is also a bunch of TopoSolitario's ikubes, great (and free) terrain pieces for sci-fi gaming, designed to be stored flat.
A few vehicles: some cars by GrendelsMother64, TopoSolitario's UOT7 Chicharra and Chris Roe / Genet Models' TA-160 Shrike, Finger and Toe Models' S-Cube and Grey Matter Games' Camel FAAV.
A lot of tiles from Fat Dragon Games' Capital City set, mounted on foamboard. There are also a couple of foamboard tiles that I just painted green and added some flock, to use as gardens or parks in city layouts.
An assortment of crates and props including TopoSolitario's ISO containers, dumpsters from the Capital City set, Tommygun's air cargo containers, a bunch of Dave Graffam's crates and packs, and pieces of Genet Models' Itoyo robot turned into terrain props.
A lot of crosspiece ruins from Dave Graffam, which are possibly some of the most cost-effective terrain pieces to use in post-apocalyptic games. Even if you just leave a bunch of them piled up you can make a good-looking area filled with debris.
There are also some other pieces from Finger and Toe Models sets: Sci-Blocks and Shantytowns. I did not build these as fold-flat because they take so little space anyway. I still have to build some elements from the Slagtown sets too.
And lastly, a good amount of terrain templates cut from "foamies," some of them covered with suede paper.
After quite some time fiddling with terrain pieces and trying different scales, I am satisfied with this set of terrain... and there is still room in that box for some more buildings and props. Now it is a matter of putting them to use. To start, I intend to go back to playing All Things Zombie...