An Untapped Source of Lithium Has Just Been Found in the US

Nature article: https://www.nature.com/articles/s41598-024-58887-x

Produced water is from 100-200 ppm Li (median in SW or NE PA, respectively).

Estimated this could yield a few thousands tons of Li a year, which isn't that much.

tl;dr: There are amounts of lithium in fracking wastewater that can be retrieved.