  We revisit a set of dark sector models, motivated by anomalies observed in
$B$ decays and the muon anomalous magnetic moment, in the light of a recently
reported diphoton excess around 750$\,$GeV. Interpreting the excess as a scalar
resonance associated with the symmetry breaking sector of a dark gauge group,
we show that a diphoton cross section of few fb can be accomodated, together
with anomalies in $R_K$ and $g_\mu-2$ within a minimal dark sector model. The
resulting prominent collider signatures are in the form of wide resonant
signals into top and muon pair final states below $\sim1\,$TeV. The model
further predicts a dark matter candidate, yet with a significantly
underabundant relic density, unless produced by an appropriate non-thermal
mechanism.
