If you’re ever in Manchester, the John Rylands Library mentioned here is one of the local jewels and absolutely worth the visit.
If you are a library connoisseur, there are also Chatham’s (one of the oldest libraries in the land, and likely the oldest dedicated to music), the Pantheon-inspired Central Library, and the elusive (and exclusive) Portico. The Law Library was pretty striking too but sadly they moved and the original building was sold.