The British Museum published the first catalogue of its library of printed books, Librorum impressorum qui in Museo Britannico adservantur catalogus, in 2 volumes in 1787.
Breslauer & Folter, Bibliography: Its History and Development (1984) no. 109.
When I last searched in August 2019 no digital facsimile of the first edition of the British Museum catalogue was available. On the other hand, several facsimiles of the second edition, expanded to 7 vols. from 1813-19 were available.