Now that we're putting together a more fleshed-out tech tree, we need buildings to go along with them. Check the tech tree thread or the wiki to see what the new techs are. Another consideration - in normal Civ4, there's a pretty straightforward progression of buildings. There's an ancient or classical version of a building, and then a renaissance-to-modern version or two, which improves the original. Like so - Library -> University Market -> Grocer -> Bank Courthouse -> Jail We don't have those upgrades. By and large, there's only one building that improves each part of the game. So the easiest way to brainstorm would be look for preliminary or improvements to the ancient buildings. For example, with Logging (an early tech) the player should be able to build Stockades, a weaker, wooden wall. City Walls, later, are now the improvement to that.