A link from Alin Suciu’s blog drew my attention to a discovery: that the British Museum (not the British Library) searchable database of its holdings also includes papyri. A search on “coptic” lists quite a number; and if you search for just images, you get back a goodly quantity of papyri.
Dr Suciu has already discussed the first of these, which is a portion of Jeremiah in Coptic. I see that there is a “Please contact us” link at the foot of each page, for additions and corrections, and I hope Dr. S. points them to his blog entry.
There are some six pages of fragments and leaves online. I think we can leave it to Dr Suciu to evaluate these. Let us hope that the BM put more images online!
If you search for “greek papyrus”, then you also get results. They seem to be documentary texts, not unnaturally enough. But I did find one of the Greek magical papyri here, mixed with Demotic spells.