  The existence of approximately 30 noncentrosymmetric metals (NCSM) suggests a
contraindication between crystal structures without inversion symmetry and
metallic behavior. Those containing oxygen are especially scarce. Here we
propose and demonstrate a design framework to remedy this property disparity
and accelerate NCSM-oxide discovery: The primary ingredient relies on the
removal of inversion symmetry through displacements of atoms whose electronic
degrees of freedom are decoupled from the states at the Fermi level. Density
functional theory calculations validate this crystal--chemistry strategy, and
we predict a new polar ruthenate exhibiting robust metallicity. We demonstrate
that the electronic structure is unaffected by the inclusion of spin-orbit
interactions (SOI), and that cation ordered SrCaRu$_2$O$_6$ exhibits a large
thermopower anisotropy ($\left|\Delta\mathcal{S}_\perp\right|\sim6.3 \mu
\textrm{V K}^{-1}$ at 300 K) derived from its polar structure. Our findings
provide chemical and structural selection guidelines to aid in the search of
new NCS metals with enhanced thermopower anisotropy.
