  We study the topological properties of magnon excitations in a wide class of
three dimensional (3D) honeycomb lattices with ferromagnetic ground states. It
is found that they host nodal ring magnon excitations. These rings locate on
the same plane in the momentum space. The rings can be gapped by
Dzyaloshinskii-Moriya (DM) interactions to form two Weyl points with opposite
charges. We explicitly discuss these physics in the simplest 3D honeycomb
lattice, the hyperhoneycomb lattice and show drumhead and arc surface states in
the nodal ring and Weyl phases, respectively, due to the bulk-boundary
correspondence.
