  W-CDF-S, ELAIS-S1, and XMM-LSS will be three Deep-Drilling Fields (DDFs) of
the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST), but their
extensive multi-wavelength data have not been fully utilized as done in the
COSMOS field, another LSST DDF. To prepare for future science, we fit source
spectral energy distributions (SEDs) from X-ray to far-infrared in these three
fields mainly to derive galaxy stellar masses and star-formation rates. We use
CIGALE v2022.0, a code that has been regularly developed and evaluated, for the
SED fitting. Our catalog includes 0.8 million sources covering
$4.9~\mathrm{deg^2}$ in W-CDF-S, 0.8 million sources covering
$3.4~\mathrm{deg^2}$ in ELAIS-S1, and 1.2 million sources covering
$4.9~\mathrm{deg^2}$ in XMM-LSS. Besides fitting normal galaxies, we also
select candidates that may host active galactic nuclei (AGNs) or are
experiencing recent star-formation variations and use models specifically
designed for these sources to fit their SEDs; this increases the utility of our
catalog for various projects in the future. We calibrate our measurements by
comparison with those in well-studied smaller regions and briefly discuss the
implications of our results. We also perform detailed tests of the completeness
and purity of SED-selected AGNs. Our data can be retrieved from a public
website.
