  We investigate the nightmare scenario of dark sectors that are made of
non-abelian gauge theories with fermions, gravitationally coupled to the
Standard Model (SM). While testing these scenarios is experimentally
challenging, they are strongly motivated by the accidental stability of dark
baryons and pions, that explain the cosmological stability of dark matter (DM).
We study the production of these sectors which are minimally populated through
gravitational freeze-in, leading to a dark sector temperature much lower than
the SM, or through inflaton decay, or renormalizable interactions producing
warmer DM. Despite having only gravitational couplings with the SM these
scenarios turn out to be rather predictive depending roughly on three
parameters: the dark sector temperature, the confinement scale and the dark
pion mass. In particular, when the initial temperature is comparable to the SM
one these scenarios are very constrained by structure formation, $\Delta N_{\rm
eff}$ and limits on DM self-interactions. Dark sectors with same temperature or
warmer than SM are typically excluded.
