  (abridged) We present an account of known cataclysmic variables (CVs) that
were detected as X-ray sources in eROSITA X-ray surveys and have Gaia DR3
counterparts. We address standard CVs with main sequence donors and white
dwarfs accreting via Roche-lobe overflow (RLOF) and related objects, the double
degenerates (DDs), and the symbiotic stars (SySts). We discern between
nonmagnetic (dwarf novae and nova-like objects) and magnetic CVs (polars and
intermediate polars (IPs)). In the publically available eROSITA catalog from
the recent DR1, typically 65\% of known cataloged and classified CVs are
detected. This fraction rises to over 90\% if the stack of all \ero X-ray
surveys (called S45 in this paper) is considered and the search volume is
restricted to a radius of 500\,pc. We examine the various classes of CVs in
various diagnostic diagrams relating X-ray and optical properties (luminosity,
absolute magnitude, color, X-ray spectral hardness, and optical variability)
and establish their average class properties. We derive spectral properties for
the 22 brightest polars and confirm an increase in the ratio of soft to hard
X-rays with increasing magnetic field in the accretion region. We report three
new soft IPs and present a spectral analysis of all soft IPs. Their blackbody
temperatures agree well with published values. The DDs represent the bluest and
faintest subcategory but reach the same identification fraction as the standard
CVs. The SySts are the most distant systems; only 20 (13\%) were detected as
X-ray sources in S45, and 7 of those are first-time detections. We investigate
their mean properties using an upper limit on the flux of the nondetected CVs.
Their X-ray nondetection is indeed a distance effect.
