Searches for rare single top quark associated production processes at the LHC

Run 2 of the LHC has witnessed the observation of many rare top quark production processes predicted by the Standard Model and has boosted searches for flavour- changing-neutral-current interactions of the top quark, that are heavily suppressed in the SM. In this contribution the highlights are shown of searches by the ATLAS experiment for rare processes involving single top quarks in association with Standard Model gauge bosons. The recent observation of associated production of a single top quark with a photon completes the list of processes and adds sensitivity to the EW couplings of the top quark.