  The negatively charged silicon vacancy ($\mathrm{V_{Si}^-}$) in silicon
carbide is a well-studied point defect for quantum applications. At the same
time, a closer inspection of ensemble photoluminescence and electron
paramagnetic resonance measurements reveals an abundance of related but so far
unidentified signals. In this study, we search for defects in 4H-SiC that
explain the above magneto-optical signals in a defect database generated by
Automatic Defect Analysis and Qualification (ADAQ) workflows. This search
reveals only one class of atomic structures that exhibit silicon-vacancy-like
properties in the data: a carbon antisite ($\mathrm{C_{Si}}$) within
sub-nanometer distances from the silicon vacancy only slightly alters the
latter without affecting the charge or spin state. Such a perturbation is
energetically bound. We consider the formation of $\mathrm{V_{Si}^-+C_{Si}}$ up
to 2 nm distance and report their zero phonon lines and zero field splitting
values. In addition, we perform high-resolution photoluminescence experiments
in the silicon vacancy region and find an abundance of lines. Comparing our
computational and experimental results, several configurations show great
agreement. Our work demonstrates the effectiveness of a database with
high-throughput results in the search for defects in quantum applications.
