  Dwarf galaxies have been extensively studied in the Local Group, in nearby
groups, and selected clusters, giving us a robust picture of their global
stellar and dynamical properties in particular locations in the Universe.
Intense study of these properties has revealed correlations between them,
including the well known universal stellar mass-metallicity relation. However,
since dwarfs play a role in a vast range of different environments, much can be
learned about galaxy formation and evolution through extending the study of
these objects to various locations. We present MUSE spectroscopy of a sample of
56 dwarf galaxies as a follow-up to the MATLAS survey in low-to-moderate
density environments beyond the Local Volume. The dwarfs have stellar masses in
the range of $M_{*}/M_{\odot}$ = 10$^{6.1}$-10$^{9.4}$ and show a distance
range of D = 14-148 Mpc, the majority (75%) of which are located in the range
targeted by the MATLAS survey (10-45 Mpc). We thus report a 75% (79% for dwarf
ellipticals) success rate for the semi-automatic identification of dwarf
galaxies in the MATLAS survey on the here presented subsample. Using pPXF full
spectrum fitting, we determine their line-of-sight velocity and can match the
majority of them with their massive host galaxy. Close inspection of their
spectra reveals that ~30% show clear emission lines and thus star formation
activity. We estimate their stellar population properties (age and metallicity)
and compare our results with other works investigating Local Volume and cluster
dwarf galaxies. We find that the dwarf galaxies presented in this work show a
systematic offset from the stellar mass-metallicity relation towards lower
metallicities at the same stellar mass. A similar deviation is present in other
works in the stellar mass range probed in this work and might be attributed to
the use of different methodologies for deriving the metallicity.
