In Riverview, there is a terrain paint that surrounds the 2 story warehouse by the science facility, and it also surrounds the indoor community pool. It is a diagonal stone pattern with weeds in between the cracks. It's a really nice terrain paint, however it can't be found in the catalog, and if you move a lot with that paint on it to another town, that paint disappears. :(
Another issue: In Twinbrook, across from the science facility is a warehouse similar to the one in Riverview. It doesn't show up as a lot, you can't build on it or delete it. It has no map tag.