Erm. Which ones aren't used? Standard goods (tier 1, 2, 3) are the ones you open early on, yes. But later, you will use the next three (standard + 1) for sentient goods and the final three (standard + 2) for ascended [this is new to chapter 18, which just opened]. So they've already done this, I think? Because both sentient and ascended goods are part of the research/tech tree.