Mech City is a 3D printable line of cute mecha, accessories, little people, and play sets! The Mech City Play Set contains hex tiles of different count sizes, roads and overpasses, and a modular building that can be assembled in a number of different ways. The printed hexes are about 70mm (~2.75") across and will quickly fill up a shelf. The hex tiles and city buildings and roads would work well for a miniatures game board, though you'd have to experiment to see how small you can get everything.
Update v1.2 - added a hex pattern to the hex tiles in case of miniatures and such :)