The tetraevangelion Bodmer 25=Greg.-Aland 556 has now been digitized and is available at E-codices (Virtual manuscript library of Switzerland) here (via Jac Perrin who suggested to the people in charge that the MS be digitized.)
There are many, many more digitized MSS out there – we have mentioned many on this blog. A few examples that I have looked at recently: the Bayerische Staatsbibliothek in Munich has put some Greek MSS on-line, including Gr. 472 (fols. 1-2, 372-373 = Greg.-Aland L1570) here.
Two other MSS that have been on-line for many years are Magdalen College, Oxford MS. Gr. 7 = Greg.-Aland 1907 and Gr. 9 = Greg.-Aland 57.