"The Hoarder" was a collector of treasures from across time and space, who would employ time travellers to do his collecting for him. He had set up operations across multiple time periods, with shutting them all down being a priority for the Time Agency. (COMIC: A New Beginning, Old Friends)
Missy saw the Hoarder imprisoned in Stormcage Containment Facility when she went to break out her earlier incarnation. (COMIC: The Master Plan)