Interesting... in addition to the Connies and a Romulan Bird of Prey, we've got some older designs -- a Y-class Earth Cargo Services freighter, a
Suurok-class Vulcan ship, and a DY-series sleeper ship, plus those two little ones in the middle that I don't recognize. The book blurb refers to "ships of various origins" surrounding the anomaly featured in the book, so maybe this is a Delta Triangle/"The Void" type of thing where it's been trapping ships for centuries.