  Based on a recently developed framework, we conduct classifications of
time-reversal symmetric topological superconductors with conventional pairing
symmetries. Our real-space approach clarifies the nature of boundary modes in
nontrivial phases. The key difference from the calculations for topological
crystalline insulators originates from the appearance of vortex zero modes on
the interface of several two-dimensional topological superconductors. We find
that our classification is complete in the $K$-theory sense for all rod groups,
all layer groups, and 159 out of 230 space groups. Our results shed new light
on superconductors with conventional pairing as candidates for topological
superconductors.
