  By means of the Lie algebra expansion method, the centrally extended
conformal algebra in two dimensions and the $\mathfrak{bms}_{3}$ algebra are
obtained from the Virasoro algebra. We extend this result to construct new
families of expanded Virasoro algebras that turn out to be infinite dimensional
lifts of the so-called $\mathfrak{B}_{k}$, $\mathfrak{C}_{k}$ and
$\mathfrak{D}_{k}$ algebras recently introduced in the literature in the
context of (super)gravity. We also show how some of these new
infinite-dimensional symmetries can be obtained from expanded Ka\v{c}-Moody
algebras using modified Sugawara constructions. Applications in the context of
three-dimensional gravity are briefly discussed.

High Energy Physics - Theory