ISS Enterprise-D

In a mirror universe, a Terran Empire starship, Galaxy-class attack cruiser, Empire registry NCC-1701-D. In one possible permutation of the mirror universe timeline, this vessel was commanded by Jean-Luc Picard. ("Dark Mirror" [Pocket TNG HC]).

Most current depictions of the mirror universe portray Terran Empire as having fallen long before the inception of the Galaxy-class, so Duane's "Dark Mirror" novel must take place in yet another alternate timeline of the mirror universe.