Documentation

Can the Grids library work with 3D uneven terrain? Yes, it can. You have to figure out how to deal with the height, though (getting it from ray casts or height maps, for example).
Does Grids support irregular grids? Not straight out of the box. However, it does make it easy to implement certain kinds of irregular grids. These include grids where cells span over multiple cells of a regular grid, and jittered grids. You can also roll out your own periodic grids with arbitrary polygons.
Can Grids be used to build an interesting GUI in Unity? Yes, indeed. It’s simple to use cells as buttons, and Grids works well with GUI packages such as EZGUI, NGUI and 2D Toolkit. (The last is particular nice to use with grids, as it allows you to make polygon colliders with ease).
Can Grids handle massive worlds? Yes. Here is an example of a grid with 250 000 hexes.

Features