Chemically peculiar stars are stars, usually giant stars, that contain anomalous amounts of rare metals within them. Examples include barium stars, lead stars, and apparently technetium stars.
One example is Przybylski's Star, about 370 light years away, which has colossal concentrations of rare-earth metals, 1000 to 10,000 times as much as in our Sun. Based in this, that would suggest that there is an entire earth mass of lanthanum alone inside this star, and probably similar amounts of other rare earths. Or a technetium star. Imagine having enough technetium to build starships and palaces out of the stuff...hmm, this belongs in my timeline somewhere. The Technetium Palace. Catchy short story name.
Would having such enormous amounts of certain metals on hand be useful to, say, a borderline Type II civilization that has a reach of several hundred light years. And what would they do with this?