  A new dark sector consisting of a pure non-abelian gauge theory has no
renormalizable interaction with SM particles, and can thereby realise
gravitational Dark Matter (DM). Gauge interactions confine at a scale
$\Lambda_{\rm DM}$ giving bound states with typical lifetimes $\tau \sim M_{\rm
Pl}^4/\Lambda^5_{\rm DM}$ that can be DM candidates if $\Lambda_{\rm DM} $ is
below 100 TeV. Furthermore, accidental symmetries of group-theoretical nature
produce special gravitationally stable bound states. In the presence of generic
Planck-suppressed operators such states become long-lived: SU$(N)$ gauge
theories contain bound states with $\tau \sim M_{\rm Pl}^8/\Lambda^9_{\rm DM}$;
even longer lifetimes $\tau= (M_{\rm Pl}/\Lambda_{\rm DM})^{2N-4}/\Lambda_{\rm
DM}$ arise from SO$(N)$ theories with $N \ge 8$, and possibly from $F_4$ or
$E_8$. We compute their relic abundance generated by gravitational freeze-in
and by inflationary fluctuations, finding that they can be viable DM candidates
for $\Lambda_{\rm DM} \gtrsim 10^{10}$ GeV.
