Salonius' Slave Store was a shop in a pocket universe encountered by the Thirteenth Doctor. Run by Salonius and his Roman legionaries stranded in the pocket universe, it traded in slaves they made out of its other inhabitants.
When the Doctor entered the pocket universe from Hydra Hall on the search for Yaz, a stallholder directed her to Salonius' Slave Store for help, where the Doctor found out from two guards that Yaz had sold straight away to the butterfly man. (COMIC: Hydra's Gate)