Thomas Baumgarte, Carsten Gundlach and CENTRA member David Hilditch recently examined the behavior of spacetimes in which black holes almost form, with the collapse driven by electromagnetic waves. They find similar behavior to that found in spherical setups-- but with subtle differences that so far evade explanation!
The work is accepted for publication in physical review letters: https://journals.aps.org/prl/accepted/c707fY01W9b1ed6941876975a33bb0149376dfc6a
A preprint is available at: https://arxiv.org/abs/1909.00850
