  Non-simply connected Calabi-Yau threefolds play a central role in the study
of string compactifications. Such manifolds are usually described by
quotienting a simply connected Calabi-Yau variety by a freely acting discrete
symmetry. For the Calabi-Yau threefolds described as complete intersections in
products of projective spaces, a classification of such symmetries descending
from linear actions on the ambient spaces of the varieties has been given in
the literature. However, which symmetries can be described in this manner
depends upon the description that is being used to represent the manifold. In
recent work new, favorable, descriptions were given of this data set of
Calabi-Yau threefolds. In this paper, we perform a classification of cyclic
symmetries that descend from linear actions on the ambient spaces of these new
favorable descriptions. We present a list of 129 symmetries/non-simply
connected Calabi-Yau threefolds. Of these, at least 33, and potentially many
more, are topologically new varieties.
