  Wachter-Zeh in [42], and later together with Raviv [31], proved that
Gabidulin codes cannot be efficiently list decoded for any radius $\tau$,
providing that $\tau$ is large enough. Also, they proved that there are
infinitely many choices of the parameters for which Gabidulin codes cannot be
efficiently list decoded at all. Subsequently, in [41] these results have been
extended to the family of generalized Gabidulin codes and to further family of
MRD-codes. In this paper, we provide bounds on the list size of rank-metric
codes containing generalized Gabidulin codes in order to determine whether or
not a polynomial-time list decoding algorithm exists. We detect several
families of rank-metric codes containing a generalized Gabidulin code as
subcode which cannot be efficiently list decoded for any radius large enough
and families of rank-metric codes which cannot be efficiently list decoded.
These results suggest that rank-metric codes which are
$\mathbb{F}_{q^m}$-linear or that contains a (power of) generalized Gabidulin
code cannot be efficiently list decoded for large values of the radius.
