Two of the earliest extant copies of the Book of Revelation with illumination cycles can be found online.
The Valenciennes Apocalypse (St Amand, 9th century): [link]
The Trier Apocalypse (9th century): [link]
Images of a recently discovered ninth-century fragment of an illuminated apocalypse with Bede’s Commentary can be found here. (For a report on a conference analysing the fragment, in German, see here).