Very much like with the system for fishing up and digging up random items that have decayed in the world and otherwise disappeared, I think it would be extremely cool to find stuff from a previous world as you were digging around, maybe have different tools for it than mining, like chisels and such, with the fossilized versions of items being mostly decorative or curios, or as a possible source of rare metals. Mostly just to avoid them simply being a way of recovering high quality equipment early in a world start.
+ would be cool if recovered PVPer gear had the name of those who wore them in battle or some vague title alluding to the kill counts achieved by them, maybe even have a whole mechanic / minigame around trying to study, not as in curio-study but actually learn things about the item based on the quality of your magnifying glass and per*int or something.
I think it would be a nice source of flavor anyway.