No idea really, but, if I were to hazard a few guesses:

1. Black Metal Armour components
2. Black Metal Arrows would be an obvious pick
3. Black Metal Spear (missing weapon for BM tier)
4. Black Metal Great Hammer (missing BM tier)
5. Crossbow from shown images (looks like Black Metal to me)
6. New forge upgrades probably
7. Maybe a new building component
8. Black Metal Great Axe possibly?
9. A new BM pick axe? for harvesting Marble?

Just to name a couple off the top of my head. I also had an idea for using Black Metal & other materials to make an armour to be equipped to Lox, to make them even more tanky, or even a back mounted Howdah, so you can shoot off the back of it.