Expanded Construction offers 14 new outdoor buildings and 11 new interior decorations. It also changes the price & value of Building Materials. There's an unbalanced mod if you want to simply play around, and a more balanced mod if you want to stay immersed in the game world.
Version 3: Complete cheating. Every building costs only 1 building material to construct. Building Materials stack to 100 and weigh nothing. Build anything you want!