  Research on topological physics of phonons has attracted enormous interest
but demands appropriate model materials. Our {\it ab initio} calculations
identify silicon as an ideal candidate material containing extraordinarily rich
topological phonon states. In silicon, we identify various topological nodal
lines protected by glide mirror or mirror symmetries and characterized by
quantized Berry phase $\pi$, which gives drumhead surface states observable
from any surface orientations. Remarkably, a novel type of topological nexus
phonon is discovered, which is featured by double Fermi-arc-like surface states
and distinguished from Weyl phonons by requiring neither inversion nor
time-reversal symmetry breaking. Versatile topological states can be created
from the nexus phonons, such as Hopf nodal link by strain. Furthermore, we
generalize the symmetry analysis to other centrosymmetric systems and find
numerous candidate materials, demonstrating the ubiquitous existence of
topological phonons in solids. These findings open up new opportunities for
studying topological phonons in realistic materials and their influence on
surface physics.
