  Very recently the LHCb Collaboration reported the discovery of two open charm
tetraquark states, $X_{0}(2866)$ and $X_{1}(2904)$. In the present work, we
study the $D^{(\ast)}$ and $\bar{K}^{(\ast)}$ interaction in the one-boson
exchange model and show that the $X_{0}(2866)$ can be understood as a
$D^{\ast}\bar{K}^{\ast}$ molecule with $I(J^{P})=0(0^{+})$, or at least it has
a large molecular component. On the other hand, the $X_{1}(2904)$ can not be
interpreted as a molecular state. Inspired by the discovery of the $X_0(2866)$
and the fact that the $D^*\bar{K}^*$ interaction is strong enough to generate a
bound state, we also discuss likely existence of other open charm molecules. In
the meson-meson sector, two molecules near the mass thresholds of $DD^{\ast}$
and $D^{\ast}D^{\ast}$ with $I(J^{P})=0(1^{+})$ are obtained, and using the
heavy quark flavor symmetry their $\bar{B}\bar{B}^{\ast}$ and
$\bar{B}^{\ast}\bar{B}^{\ast}$ counterparts are also predicted. In the
meson-baryon sector, 7 open charm molecules with $I=1/2$ near the mass
thresholds of $D^{(\ast)}\Sigma_{c}^{(\ast)}$ naturally appear, as dictated by
the heavy quark spin symmetry.
