The housing ladder, and the one that took two sources
Four games' housing ladders, three of them straightforward. Zeus needed a fansite and an engine together, and the join between them is what makes it trustworthy.
The rung a citizen lives on is what half the series' mission goals are written against — five thousand people in a townhouse or better — so it belongs on the site as a table rather than a sentence. Pharaoh's came whole out of Akhenaten: twenty rungs with capacity, prosperity, desirability thresholds and ten requirement columns, each stated five times, once per difficulty.
Caesar III's is deliberately thinner. Names and footprints only, because its requirements live in c3_model.txt — the same absence as the missing cost column, for the same reason. Reading it also caught a trap: the buildings table stores houses alphabetically, so Grand insula sorts first. The ladder order is the enum order, and only the enum knows it.
Zeus was the interesting one. A fansite names the eleven rungs and gives each one's population but describes requirements qualitatively — "oil + appeal". eZeus, a live reimplementation, carries the exact conditions in its evolution code but reads the names from the game's language file, which does not ship in the repository. Neither source is sufficient alone.