To complement and extend the reach of ATLAS, CMS and LHCb for new long lived particles, a number of auxiliary detectors at the CERN complex have been proposed. I will review the various proposals, with an emphasis on the CODEX-b detector, which would be located in the DELPHI/LHCb cavern. Time permitting, I will also briefly discuss a new, more speculative idea for an experiment of this type.