  A model-independent search for new physics leading to final states containing
$H\rightarrow\gamma\gamma$ decays is performed with 139 fb$^{-1}$ of $\sqrt{s}$
= 13 TeV pp collision data recorded by the ATLAS detector at the Large Hadron
Collider at CERN. This search examines 22 final states categorized by the
objects that are produced in association with the Higgs boson. These objects
include isolated electrons or muons, hadronically decaying $\tau$-leptons,
additional photons, missing transverse momentum, and hadronic jets, as well as
jets that are tagged as containing a b-hadron. No significant excesses above
Standard Model expectations are observed and limits on the production cross
section at 95% confidence level are set. Detector efficiencies are reported for
all 22 signal regions, which can be used to convert detector-level
cross-section limits reported in this paper to particle-level cross-section
constraints.
