Here is a list of online resources relating to the Herculaneum Papyri. Some are in Italian or German but the essential information is usually accessible without extensive knowledge of the languages. 

CISPE, the international centre for the study of Herculaneum Papyri in Naples. Includes overview of the Content of the published Volumes of Cronache Ercolanesi and La Scuola di Epicuro.

Online catalogue of Herculaneum Papyri 

List of online editions of the Herculaneum texts Amalgamated catalogue of papyri worldwide including the Herculaneum Papyri with related materials. An ongoing international project. 

Bibliography on the Herculaneum Papyri (Oxford Bibliographies Online). Subscription required. An earlier version covering titles up to 2006 can be found here.

Bibliography on Philodemus of Gadara (Oxford Bibliographies Online). Subscription required.

Leuven Database of Ancient Books

The Oxyrhynchus Papyri

Oxford Facsimiles of Herculaneum Papyri

P.Herc. 118: images of the original papyrus roll in the Bodleian Library

Images of Herculaneum Papyri in Naples

Images of Herculaneum Papyri in Windsor Castle Library

Online catalogue of archive of the Officina dei Papiri

Published engravings of Herculaneum Papyri: Collectio Prior; Collectio Altera