I noticed that those floor tiles are basically a material surface with a filtered texture surface (rough, brick, etc) on top... Is it possible to create a script that applies the texture to the floor tile surface and then render it to a .png file?
The reason why this might be important is, if we are going to make random surfaces to break the tiling effect up a bit, it would be incredibly time consuming to simply render all those different tiles by hand for any given change, forcing us to make fewer changes. Plus this allows us to do other things, like create random textures in addition to the random surfaces, which would increase the number of floor tiles by around 16 times, but with a script the person who implements this won't have to render 16 different sets of floor tiles.
Also, is it possible to get the raw files for those floor tiles? That way other people can work on getting them to tile better. One thing I think they could use would be some more outline, so they fit more with the artistic theme of the rest of the graphics.
edit--upon further inspection, it looks like the method used (take a photo of a material, apply a texture to it) would only really work for the rough, smooth, and engraved aspects. For the block and stone walls and floors, the texture pattern would have to be broken up (this is easy with the block pattern; just rotate and jumble up four squares, but for the stone walls and floors, something more random will be necessary).