English artists Arnold Machin and Ian Rank-Broadley each produced portraits of Queen Elizabeth II that were used on the obverse of hundreds of different coin types throughout the UK and the Commonwealth. However, each of them also produced a few reverse designs. For example, Machin created the reverse designs of the 1966 circulation coins of the Bahamas.
It would be nice to be able to search for those designs via a specific query, but searches on engraver do not differentiate between obverse and reverse. Would that be a feasible request? At present I would have the unenviable task of searching through hundreds of records, in the cases of Machin and Rank-Broadley.