A couple of the larger resources for searching materials in Coptic include APIS, housed at Columbia, for papyri, and CMCL, based in Rome, for manuscript material, including the works of Shenoute the Archimandrite.
They’re works in progress: check if your institution’s collections have been fully uploaded. US member institutions of APIS include UC-Berkeley, CSU-Sacramento, the University of Chicago, Columbia, Duke, Michigan, NYU, Penn, Princeton, SMU, Stanford, Union Theological Seminary, Washington State-Pullman, Wisconsin and Yale. Members of CMCL include Columbia, Michigan, the Pierpont Morgan Library, and Yale.
There used to be a romanization table available for Coptic, included in the Greek table. Since the updating of the Greek table, this is no longer the case, but a new table for Coptic is expected to be drafted later. In the meantime, a guide can be found here.