  In the theory of dilute magnetic impurities in superconductors, the effect of
all impurity spin-components is expressed via a single magnetic scattering rate
$\Gamma_\mathrm{m}$. In a more realistic setting, magnetic impurities are
anisotropic. In this case, the spatial randomness of three spin-components of
impurities gives rise to generally different scattering rates $\Gamma_i$
($i=1,2,3$). We explore the effects of anisotropic magnetic impurities on the
in-plane critical field in 2D superconductors. We discuss singlet, triplet and
parity-mixed order parameters allowed in systems without the inversion center.
Also, the addition of a small amount of magnetic impurities may cause singlet
to triplet crossovers. In all cases, different components of impurity spin
affect the magnetic field -- temperature phase diagram differently. We show
that anisotropy of the magnetic impurities can serve as a probe of
unconventional triplet or parity-mixed superconductivity.
