The majority of hot subdwarfs lie on or close to the helium main-sequence. Many have hydrogen-rich surfaces, but a substantial fraction have hydrogen-depleted or hydrogen-deficient surfaces. Amongst the former, three were known to show extraordinary overabundances of heavy elements including zirconium and lead. A limited survey with Subaru/HDS revealed three new lead-rich subdwarfs. A much wider survey is in progress using SALT. Discoveries include two new extreme helium stars, new intermediate helium subdwarfs, and a new lead star. Analysis of the growing sample shows evidence of connections between hydrogen-deficient classes.