I learn from here via here that Juan Garces, the go-ahead curator of Greek manuscripts at the British Library, has got 284 manuscripts online. It’s well worth browsing the four pages of the list. There’s a manuscript of Zosimus New History in there, for instance. Despite pleas from Biblical people, it’s mostly classical or patristic or bits and pieces, which is all to the good. Synesius is well-represented too.
Note that the short list in the browse is not everything. If you click on one of the text links you get a break down of all that the manuscript contains. Works in the TLG are given the TLG reference too.
Turning the pages is quick and easy, thankfully, unlike early and very clunky online interfaces. This one is almost usable!